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Genetics 101 + = ? ~a genetics tutorial~ ____________ basic genetics for the non-genetecist via gerbils for the non-rodent enthusiast mr. e ~ SRCS ~ fall 2005
Genetics 101 Contributions and dedications Eric Proffit fall 2002 -4 David Schulker spring 2003 -4 Stephen Potter fall 2002 -2005 Chad Peets spring 2003 -6 Christopher Oliver winter 2004 -6 John Magill winter 2004 -5 Bennett winter 2004 -5
Genetics 101 macro What happens when you combine peas and the church?
Genetics 101 + Peas = the Church Who: Father Johann Gregor Mendel Where: a monastery in Austria What: Developed hereditary theories When: 1850’- 1860’s (just before US civil war) Father of Modern Genetics
Genetics 101 • Macro-history • His early adult life was spent in relative obscurity Gregor Mendel doing basic genetics research 1822 -1884 and teaching high school mathematics, physics, and Greek in Brunn (now in the Czech Republic). • In his later years, he became the abbot of his monastery and put aside his scientific work. • His ideas had been published in 1866 but largely went unrecognized until 1900, which was long after his death.
Genetics 101 • Macro-history Mendel's research reflected his personality. Once he crossed peas and mice of different varieties (separately, that is) "for the fun of the thing, " and the phenomena of dominance and segregation "forced themselves upon notice. " • He saw that the traits were inherited in certain numerical ratios. He then came up with the idea to set out to test it more vigorously using the common pea (Pisum sativum). + ?
Genetics 101 • Mendel studied seven basic characteristics of peas: 1. flower color 4. seed shape 2. flower position 5. seed color 3. stem length 6. pod shape 7. pod color By tracing these characteristics, Mendel discovered three basic principles which governed the passage of a trait from one member of a species to another member of the same species.
Genetics 101 • Mendel’s conclusions 1. that the inheritance of each trait is determined by "units" or "factors" that are passed on to descendents unchanged (these units are now called genes ) 2. that an individual inherits one such unit from each parent for each trait 3. that a trait may not show up in an individual but can still be passed on to the next generation.
Genetics 101 So what exactly is new about all this? Significant? Doesn’t seem so…
Genetics 101 Where would we be without… The liger: lion X tigress liger I’m Samson. I stand 3. 7 m (12 feet) tall on my hind legs and weigh 500 kg (1, 100 lbs) and can run at 80 km/hr (50 mph)!
Genetics 101. Speciation: Is it immoral to hybridize animals? Ethical dilemma or freak show curiosity? Pros vs. Cons Should the advantages & disadvantages even be taken into consideration? Ethical Issues in Genetic Engineering and Transgenics By Linda Mac. Donald Glenn
Genetics 101 the Cama… I have the cloven hooves of a llama and the short ears and tail of a camel! & I can spit too! …scientists hope to combine the best qualities of both into the one animal — the superior fleece and calmer temperament of the llama with the larger size of the camel.
Genetics 101 The Zonkey… (zedonk or zebrass) The Zorse… Zebras, donkeys, and horses are all members of the family equus - Equines. They are all slightly different in genetic makeup, but still all equines. Equines can be crossbred to produce hybrids. That is, horses have 64 chromosomes, donkeys have 62. The cross between a Donkey Jack (Stallion) and a mare Horse is called a Mule. The opposite cross is a Hinny. (Mules and hinnies can be male or female, either one, but are sterile since their chromosome count is 63).
Genetics 101 I’m Kekaimalu, the world’s first and only wholphin. My smaller mom, a bottlenose dolphin, swims with me (below left) while my dad, a false killer whale is bigger & has more teeth! I’m their average! the Wholphin…
Genetics 101. What’s Next? ? Aquatic bovines… Mumu? Mt. Dew- making flies?
Genetics 101 Seriously… better yielding crops
Genetics 101 Crops with desirable features… D ef en se … (Against predators)
Genetics 101 Color…
Genetics 101 Disease resistance… Corn smu t… Wheat rust…
Genetics 101 And even livestock performance and yield!
Genetics 101 Dodo Tilacino One could resurrect a lost species such as these… Trilobite Great Auk
Genetics 101 Or these ?
Genetics 101 …or things Mendel never imagined…
Genetics 101 …not to mention the medical applications and a slew of other ethical facets to debate… GM Produce
Genetics 101 Hollywood hype …. or potential reality? Film: GATTACA (1997) [first title card] Plot: Gattaca Corp. is an Vincent: They used to say that a child Title Card: "Consider God's handiwork; aerospace firm in the future. Taglines for [Vincent is looking at the 12 -fingered pianist] During this time society analyzes conceived in love has a greater chance of who can straighten what He hath made Gattaca (1997) your DNA and determines where Irene: You didn't know? happiness. They don't say that anymore. crooked? " - Ecclesiastes 7: 13 you belong in life. Ethan Hawke's There Is No Gene For The Human Spirit. Vincent: Oh, I knew. character was born with a How do you hide when you're running from yourself? congenital heart condition which Irene: It's amazing, isn't it? Vincent: I'll never understand what would cast him out of getting a Only one criterion : genetic perfection [second title card] Vincent: Twelve fingers or one, it's how you play chance to travel in space. So in possessed my mother to put her faith in D: Andrew Niccol; with Ethan turn he assumes the identity of an Only the strong succeed Title Card: "I not only think that we will Irene: That piece can only be played with twelve. Hawke, Uma Thurman, Alan Arkin, athlete who has genes that would God's hands, rather than her local Jude Law, Loren Dean, Gore Vidal, tamper with Mother Nature, I think Mother allow him to achieve his dream of Ernest Borgnine, Blair Underwood, geneticist. space travel. wants us to. " - Willard Gaylin Tony Shalhoub. (PG-13, 108 min. )
Genetics 101 Alba & his proud owner, Eduardo Kac; transgenic artist
Genetics 101 Glow -in-thedark Alba, the fluorescent bunny. Photo: Chrystelle Fontaine B u n ni es !
Genetics 101 Book… Art exhibition in Rio
Genetics 101 Could I be genetically modified to roar?
Genetics 101 Did you know? The actor who played Wedge in the original Star Wars trilogy has a famous nephew: actor Ewan Mc. Gregor, who plays the young Obi-Wan in the new Star Wars film. Betsy Ross is the first real person to ever have been the head on a Pez dispenser! Scientists at a University in Ontario, Canada have discovered that the part of Einstein's brain thought to be related to mathematical reasoning - the inferior parietal region - was 15 percent wider on both sides than a normal brain. It’s time to get back to Mendel!
Genetics 101 • Through selective cross-breeding over many generations, Mendel discovered that certain traits show up in offspring without any blending of parent characteristics. – For instance, the pea flowers are either purple or white--intermediate colors do not appear in the offspring of cross-pollinated pea plants. • This was revolutionary because the reigning biological theory of the day suggested a blending, that is, taking our previous example, a purple flower crossed with a white flower would produce say a lavender or some such color between the parental colors…. and yet we find that this IS NOT SO!.
Genetics 101 • Lesson 1: Chromosomes & Genes MA Hi, I’m a Chromosome! As well as genetic • This is a chromosome variety! A gerbil gets half its chromosomes from its mom and the other half from its dad…this ensures pairs of chromosomes PA KID
Genetics 101 Why do we need chromosomes ? Chromosomes hold genes. (units of inheritance usually Gene here! occurring at specific locations; Physically, a gene is a sequence of DNA bases that specify the order of amino acids in an entire protein or, in some cases, a portion of a protein) There are different versions of genes, called alleles, that chromosomes carry. Some alleles are DOMINANT (overriding gene) while others are recessive (masked gene in presence of dominant).
Genetics 101 Consider Mendel’s seeds as an Here is the mathematical matrix behind the alternate way of looking at results. . . it… Smooth S S W Ss Ss rin s kl s Ss Ss ed Every single “child” must be…?
Genetics 101 • While Mendel's research It also applies to cats… was with plants, the basic underlying principles of heredity that he discovered also apply to gerbils because the mechanisms of heredity are essentially the same for both. . . and any DNA-dependent life-form!
Genetics 101 What, exactly is a gerbil? Taxonomy Order: Rodentia Suborder: Myomorpha Family: Cricetidae Sub-Family: Gerbillinae Genus: Meriones Species: unguiculatus Meriones unguiculatus What's in the name ? "Meriones" means Greek for "warrior" means So, taxanomically, I’m a means gnawing, clawed warrior!! "rodere" (rodent) "unguiculatus" I’m an SRCS natural! Latin for "with claws " "to gnaw "
Genetics 101 Origin and Habitat Mongolian gerbils (desert rat, sand rat, antelope rat, jird) are native to eastern Mongolia, northeast China, and western Manchuria. They live in a variety of terrains, including deserts, bush country arid steppes, low plains, grasslands, and mountain valleys. In 1954, eleven pairs were brought to the United States from a research laboratory in Japan. The offspring of these gerbils were the nucleus for most research colonies in the United States today.
Genetics 101 I’m a 4 toed jerboa I’m a bushy-tailed jird, a gerbil’s closest relative!
Genetics 101 Behavior & Diet Gerbils are gregarious!
Genetics 101 diurnal/nocturnal… diurnal/nocturnal (active during both day and night) sand-bathing gnawing calisthenics
Genetics 101 scratching & digging and industrious—building extensive burrows, often with several entrances. "March, 5 th, 1989: After several months, I now feel that these strange little rodents have finally accepted me as one of their own. "
Genetics 101 Some unusual behaviors… licking Food envy "Whenever any of our gerbils finds a particularly tasty bit of food, it will run into a corner and make a sudden, sharp right turn. . . to keep food away from the others. However, the comical thing about this is that the gerbil usually ends up right next to another gerbil, who tries to steal the food away from him. This behavior also occurs when there are no other gerbils around. " Gail Seigel • Thumping • Nasal greeting • Aggression winking • PEW sway Pup retrieval
Genetics 101 PEW sway All PEW’s exhibit a swaying motion which is triggered by assuming a normal stance and evidence by an unconscious drift… standing drifting return to drift again
Genetics 101 PEW sway It looks a lot like this:
Genetics 101 moulting A grown-up, faded-out Schimmel (the tail keeps its orange), and a young Schimmel (looks like a DEH).
Genetics 101 juvenile Stages of the nutmeg molt adult
Genetics 101 Some adorable pre-molt young Polar Fox (F) Spotted Silver Nutmeg (M) Spotted Agouti (M) Honey Cream (M) Ruby Eyed White (M) Spotted Black (M) Spotted Gray Agouti (F) Molting
Genetics 101 Their diet consists of seeds, leaves, stems, and roots; to some extent, food is stored in burrows (easily observed through their habit of covering their food dishes or stashing their seeds). Juveniles feeding
Genetics 101 Farming … EVERY gerbil’s dream…
Genetics 101 Uses As research animals, gerbils comprise less than 0. 5% of the total number of rodents used annually. As pets, gerbils are popular because they are curious, clean, and easy to maintain and handle. Douglas Adams was dangerously close to the mark!
Genetics 101 A sample paragraph from Finally, if Wolbachia infilarial nematodes behaves as a reproductive “Tetracycline treatment and sex-ratio distortion: a role for parasite, some of the effects of tetracycline might derive from an Wolbachia inthe moulting of filarial nematodes? ” interfer-ence with the manipulations determined by Wolbachia(Bandi et al. , 1999). We emphasise that the three M. Casiraghi J. W. Mc. Call L. Simoncini hypothesesare not mutually exclusive (see Bandi et al. , L. H. Cramer L. Sacchi C. Genchi 2001 b). Despite growing interest and intense research focused on the antifilarial effect of tetracycline and its application in therapy of J. H. Werren C. Bandi human onchocerciasis (Hoerauf et al. , 2000 a), the results of the first paper published on this subject (Bosshardtet al. , 1993) have not yet Dipartimento di Patologia Animale, been fully evaluated and discussed. In this study, tetracycline Universita` di Milano, Milan, Italy treatments were applied at differentlarval stages (L) of the filaria College of Veterinary Medicine, The University of Georgia, Athens, GA, USA Brugia pahangi in its experi-mental host (the gerbil Meriones Dipartimento di Produzione Animale, Universita` di Parma, Italy unguiculatus). The antifi-larial effects recorded in Bosshardt et al. ’s paper can be summarised as follows: Dipartimento di Biologia Animale, Universita` di Pavia, Italy Department of Biology, University of Rochester, NY, USA
Genetics 101 So far only two people have connected gerbils to a greater understanding of the laws of physics…the author of Doctor Fun and…
Here is a working example: Genetics 101 Water Balance Water gain (ml/day) Ingested in liquid 0 1500 (60%) Ingested in food 6. 0 (10%) 750 (30%) Derived from metabolism 54. 0 (90%) 250 (10%) 60. 0 (100%) 2500 (100%) Kangaroo Rat Human Water Loss (ml/day) Evaporation 43. 9 (73%) 900 (36%) Urine 13. 5 (23%) 1500 (60%) Feces 2. 6 (4%) 100 (4%) 60. 0 (100%) 2500 (100%) Source: Kangaroo Rat data from Schmidt-Nielsen. Animal Physiology: Adaptation and Environment, 4 th ed. Cambridge: Cambridge University Press, 1990, p. 339.
Genetics 101 Aesthetics… In the year 1506, the great inventor, engineer, and artist Leonardo da Vinci painted on a piece of pine wood, a young Florentine woman, Monna (or Mona) Lisa. Leonardo himself loved the portrait so much that he always carried it with him, until it was sold in France to Francois I, by Leonardo himself. Today, the Mona Lisa hangs in the Louvre Museum in Paris and is, without doubt, the most famous painting in the world. When people describe the portrait, the two words most often used are "enigmatic", meaning perplexing or baffling, and "alluring", meaning tempting, desiring, and attracting. The eyes seem to look directly at you no matter where you stand relative to her. And the smile, there is something about that smile, but what is it? No one seems to come up with a good explanation of the smile. While the smile has often been copied, no artist can quite recreate or duplicate the smile. Mongolian Lisa ca. 2005
Genetics 101 Seeing Beauty The Japanese once did a study on defining the attributes of a beautiful face of a woman, and they concluded one of the most important attributes is a relationship between the outer tips of the eyes and the center point of the lower lip. Those three points should form the ends of an equilateral triangle. Is this the key to Mona? What did this mean? I knew geometry was needed for something!
Genetics 101 Art of all sorts… Antler totem of the Gobi Judith H. Block
Genetics 101 Recognize the name? …Is this how the cosmetic giant started? . . if so…gerbils are the springboards to unimaginable entrepreneurial feats… Thomas B. ~ age 8 Mary K. ~ age 8
Genetics 101 reproduction Breeding onset is between 65 -85 days of age in females and 70 -85 days in males. Gerbils are polyestrous and breed year round; ovulation is spontaneous. The duration of the estrous cycle is 4 -6 days. Gerbils used as breeders are permanently paired (they form semi-stable annually monogamous pairs). Mating is usually, but not always, nocturnal. Spontaneous ovulation is common in mammals and is periodic, that is, based upon a definite cycle. This is contrasted with induced ovulation (certain rodents, rabbits) which is initiated by copulation.
Genetics 101 reproduction The average gestation period is 25 days. A fertile postpartum estrus occurs in 60 -85% of gerbils, and simultaneous lactation and gestation may prolong gestation up to 42 days due to delayed implantation. The average litter size is 4 -6. The young are weaned at 21 days; weaning weight is 20 -25 grams. If the postpartum estrus is not utilized, the dam resumes cycling following weaning.
Genetics 101 any all ‘start’: Romantic dinner, etc. ‘finish’ : birth! 25 days…w/nursing gap b/w
Genetics 101 newborn 1 week The young weight approximately 3 grams at birth, are hairless, and have closed eyelids and ears.
Genetics 101 Cannibalization is rare; if it does occur, the litter is usually small and is the dam’s first. The female may destroy a litter if it’s very small or if she stops lactating. This may be a wild , survival behavior. A dam may desert her litter or cannibalize it if she is disturbed , overcrowded or ill. Most females are fairly reliable mothers. …if it comforts you any: Fostering abandoned pups is possible if host dam has a litter of chickens eat chicken! similar age. A pregnant and nursing gerbil must have a constant water supply. Regularly check that the water bottle is filled and working properly. If the water bottle runs dry, the mother gerbil may have to resort to sacrificing one of her pups as a source of liquid so she can continue to nurse the litter.
Genetics 101 Sexing Male gerbils are mostly distinguished from female gerbils by noting the greater anogenital distance in the males—that is, the distance between their urinary and anal openings. This is best accomplished by lifting their tails and comparing them. male Other determinants include: female The scrotum of the male d The scent gland (m: larger; this female is older. . ) The nipples (female) The size of their body (m: larger) d
Genetics 101 If the means of your genetic research is reproduction, what do you do with all the kids?
Genetics 101 “You Gotta Eat!” We here at SRCS honor the longstanding proven tradition of the CHECKERS philosophy…
Genetics 101 Circle of life issues * note: no gerbils were harmed in the making of this tutorial
Genetics 101 Gen. Ethics. . . 26 Then God said, "Let us make man in our image, in our How is this different from Eugenics? likeness, and let them rule over the fish of the sea and the How do you decide who birds of the air, over the livestock, over all the earth, [b] and stays and who (ahem) … over all the creatures that move along the ground. " doesn’t stay? 27 So God created man in his own image, • Imago Dei Trivia: Jude Law's character in the image of God he created him; asks to be called by his • Health male and female he created them. middle name, Eugene. • Cultural "Eugene" comes from the 28 mandate • Genotypic God blessed them and said to them, "Be fruitful and Greek for "well born, " which Jerome is. "Eugenics" (the increase in number; fill the earth and subdue it. Rule over the demand eu[gen[ics 7 y 1 jen 4 iks 8 n. pl. • Stewardship science of improving the fish of the sea and the birds of the air and over every living < Gr eugencs, the movement devoted hereditary qualities of a race vs. Sanctity • Behavior creature that moves on the ground. " to improving the human species through the control of hereditary factors in mating Genesis 1: 26 -28 or breed) is the central theme of the film.
Genetics 101 Stewardship As a believer one must confront the cultural mandate as a purposedriven reality—Why? 1. Knowledge (we know about it) “God has chosen to reveal Himself” 2. Passion: a fleshing out of conforming to the Image of Christ It is a returning of nature to the Garden…a redemptive and restorative ethic! How do we do this? …how do we subdue? Naming (authority): God named Adam, Adam names living things, Adam named Eve (we name kids, pets, cars, streets, houses, etc. ) Spreading out/Exploring: Note Babel reversal of what? Cultivate/Nurture: landscaping, manicuring, trimming, mowing!…. and the list goes on!
Genetics 101 Handling A gerbil is easily lifted by scooping it up in one’s hands, where it usually remains without restraint. A gerbil can also be lifted by gently grasping the base of the tail to move the animal from one enclosure to another. or Note: Few photos are available due to professional sensitivity; attempt only if trained by an expert
Genetics 101 Showing Judging The judges will be looking out for certain things, below is a list of how the points are scored: Type - 20 Condition - 20 Colour - 20 Size - 15 Fur - 10 Ears - 5 Eyes - 5 Tail and Tuft - 5 Total = 100 Courtesy of NGS Penalty points are to be deducted as follows: Disease or intractability - Excess fat - 10 points max DISQUALIFICATION Moulting - 10 points max Sores, scabs, or wounds - Dirty/stained fur - 10 points max DISQUALIFICATION Dirty Show pen - 5 points max Missing fur - 10 points max
Genetics 101 Q: If horses eat hay and cows don’t, how A: I don’t know…motorcycles long does it take to get to the moon by bicycle? don’t have doors!
Genetics 101 Are you ready to wander into Geneland?
Genetics 101 The mother and father each have a pair of alleles on six dimensions (the loci) that control visible characteristics: A -- controls the color of the belly A C – controls coat pattern; can lighten or colorpoint (darker extremities) E -- controls the amount of yellow G -- controls the amount of gold grey P -- controls eye color/coat intensity Sp -- controls spotting Sp
Genetics 101 For the sake of simplicity, we will initially focus on the belly color--the ‘A’ locus. • Because genes can be either dominant or recessive, there does exist, at times, a tension between them. Recessive alleles only Dominant alleles “get what they want always “get what want” when paired they want” and vs with another recessive over power allele that wants the recessive alleles; same thing; these are represented by a lower represented by a case a capital A
Genetics 101 For example: There are three scenarios at the A locus which determines whether the gerbil will be self-colored (belly is same color as coat…such as. . . ) Black Silver nutmeg Nutmeg
Genetics 101 or if it will be non-self colored (belly is cream or white…such as. . . ) Dark-Eyed Honey Argente golden Golden agouti (wild color)
Genetics 101 Scenario 1: AA; homozygous dominant Scenario 2: Aa; heterozygous “same” Scenario 3: aa; homozygous recessive “other” Toddlers at 2 -3 wks (left); juveniles at 6 wks (right)
Genetics 101 Scenario 1: AA; homozygous dominant White belly! A In this scenario you would White also end up with a non-self belly! gerbil, a gerbil with a white belly. Both dominant genes want the gerbil to have a white belly. So the dominant genes agree and the gerbil is non-self. A That’s what I said… AA
Genetics 101 Scenario 2: Aa; heterozygous Solid belly! a White belly! A Oh, okay… Aa In this scenario you would end up with a non-self gerbil, a gerbil with a white belly. The dominant gene and the recessive gene disagree. But a dominant gene will always win against a recessive gene for the same trait. So the recessive gene goes along with what the dominant gene wants and the gerbil is non-self.
Genetics 101 Scenario 3: aa; homozygous recessive Solid belly! a a That’s what I said… aa In this scenario you would end up with a self-colored gerbil, a gerbil with a solid belly. Both dominant genes want the gerbil to have a solid belly. So the dominant genes agree and the gerbil is self-colored.
Genetics 101 Self-colored or non-self colored? 1. 2. Non-self: A- 3. Self: aa 4. Self: aa 5. Non-self: A-
Genetics 101 Colors? 3. golden agouti 1. lilac 2. burmese 4. darkeyed honey black 5. (DEH)
Genetics 101 Review Self A A A a a a Non-self
Genetics 101 Phenotype & Genotype The difference between a gerbil's phenotype and genotype is very simple. Look at the picture of the gerbil below and describe what its coloring looks like. Then read the row of letters next to the picture. Aa. CCEe. Gg. Ppspsp Phenotype: “white belly, golden coat with black ticking & black eyes” Genotype
Genetics 101 Your verbal description of the gerbil in the photo is its phenotype. The row of letters you read is its genotype. A phenotype and a genotype can tell you the same thing, they are just different ways of expressing it. A gerbil's genotype is basically scientific shorthand for a description of what the gerbil looks like as well as what it masks. For example, instead of saying "The gerbil has a white belly and black eyes" I could say "The gerbil is Aa. Pp".
Genetics 101 To someone that knows which traits correspond with "A" and "P", I am saying the same thing!
Genetics 101 Each locus (pair of chromosomes that determine a certain trait, represented by a pair of letters) stands for a certain trait on the gerbil. Aa stands for one trait, while CC stands for another, and spsp stands for yet another. When you are writing a genotype, the dominant alleles (CAPITAL letters) always precede the recessive alleles (lower-case letters). Remember the "geno" in genotype stands for "gene". A a
Genetics 101 A phenotype is the physical description of something: it's shape, size, color, texture, etc. Each gerbil's official coat color name is also it's phenotype. Consider the “siamese” cat? You know that means “a cat with dark points” or a “colorpoint. ”. The gerbil to the right is an "agouti". That means "a gerbil with black eyes, a golden coat with black ticking, and a white belly". Remember the "ph" in physical, as in physical description, for the "ph" in phenotype.
Genetics 101 So…. The Genotype is the actual genetic code (expressed and unexpressed/masked) A protein called the Agouti protein has a major effect on the amount of melanin injected into the growing hair. The protein causes a banding effect on the hair by triggering a sudden change from the production of eumelanin (black/brown pigment) to phaeomelanin (red/yellow pigment). An example of this coloration would be like the color of a wild rabbit. The term 'Agouti' actually refers to a South American rodent that exemplifies this type of hair. (& our wild colored gerbil!) The Phenotype of an organism is what is expressed…in other words, what it looks like…
Genetics 101 Let’s review allele pairing Match the term with the proper allele pairs: dark eyes homozygous recessive Pp heterozygous pp pink eyes homozygous dominant PP dark eyes What does the P locus code for? (rec. carrier) Eye color!
Genetics 101 Inheritance Heredity: Crash Course Biology #9 Lets say you have one agouti gerbil that you know is Aa for the 'A' locus. Her mate is a black gerbil that you know is aa. (Note: refer to your gerbil color sheet/genotype handout) What will their babies be? To find this out, you need to draw a Punnett Square. For one locus (two alleles), draw a box and divide it into four quadrants like so. . . • Punnett Square - A simple table used by geneticists to determine the outcome of various combinations of alleles.
Genetics 101 Write the male's genetics across the top, and the female's genetics down the side. Each allele should be split to border one square. P 1: Parental cross Black male: aa P 1 a a Agouti female: Aa We are now ready to cross the parents!
Genetics 101 P 1 a a A Next, complete the table by combining the pairs of the alleles as if you were multiplying two variables. P 1 a A a Their children become ‘F 1‘ which stands for first Filial generation (offspring; 1 st kids!) a a Aa Aa aa Each box must have two letters!
Genetics 101 Let’s interpret the results… These are your possibilities. P 1 a a A Aa Aa a aa The agouti and black gerbil can have babies that carry what is inside that square. Aa 2/4 = ½ Aa 50% aa aa 2/4 = ½ These percentages are called F 1 probabilities-the result of the P 1 cross 50%
Genetics 101 Let’s interpret the results… Because half of the genetic rectangle is taken by Aa, and the other half of the genetic rectangle is taken by aa, there is a 50% chance of getting babies with Aa and a 50% chance of getting babies that carry aa. You could still end up getting all Aa or all aa, but the possibility for each is there. These are your possibilities. Aa 2/4 = ½ Aa 50% aa aa 2/4 = ½ So what does this really tell you? The babies could be either self or non-self: solid bellied or white bellied…or a combo of either. 50%
Genetics 101 Let’s interpret the results… These are your possibilities. Aa + Aa Agouti female: Black male: Aa aa 2/4 = ½ 50% heterozygous aa aa So what does this really tell you? The babies could be either self or non-self 2/4 = ½ 50% homozygous recessive
Genetics 101 STEPS to determine the genotypes from parent organisms 1. write down your "cross" (mating) 2. draw a Punnett square 3. "split" the letters of the genotype for each parent & put them "outside" the P-square 4. determine the possible genotypes of the offspring by filling the squares 5. summarize results (genotypes [allele pairs & percentages] & phenotypes of offspring ) 6. bask in the glow of your accomplishment !
Genetics 101 Try your hand at another P 1 cross (focusing only on the A locus: P 1: nutmeg x arg. gold. (aa) (AA) Suppose I have a homozygous Nutmeg male and I want to breed him with a homozygous Argente Golden female. What are their probabilities of belly colors? STEP 1. write down your "cross" (mating) r t u o y shee o t er olor f e R c r l e i p b ger he pro ! t s r r i o a f p e l e all
c. The LORD ofthe GERBILS d Cage 23 Both here are homozygous at locus A! Nutmeg; m Argente golden, spotted; f aa CC ee GG Pp AA CC EE GG pp
Genetics 101 2. draw a Punnett square a a A Aa Aa A Aa 3. "split" the letters of the genotype for each parent & put them "outside" the P-square 4. determine the possible genotypes of the offspring by filling the squares 5. summarize results (genotypes [allele pairs & percentages] & phenotypes of offspring ) Shown on next slide!
Genetics 101 Let’s interpret the results… These are your possibilities. + Aa Aa Nutmeg male: Arg. gold female: aa AA 4/4 = 1 100% heterozygous Aa Aa So what does this really tell you? The babies can only be non-self! (white-bellied) only
Genetics 101 Making sense? Good. Now remember that all of the examples above only deal with the 'A' locus, but there are several other genes that affect a gerbil's coat color. There are six different loci that all play off each other, and this can result in many different color variations! Let’s try 3 loci!
Genetics 101 The mother and father each have a pair of alleles on six dimensions (the loci) that control visible characteristics; we’ll choose 3: A -- controls the color of the belly A C – controls coat pattern; can lighten or colorpoint (darker extremities) E -- controls the amount of yellow G -- controls the amount of gold grey P -- controls eye color/coat intensity Sp -- controls spotting Sp
Genetics 101 We’ll need 3 Punnett Squares… …one for each locus 1. Fill in the parents: nutmeg, m: aa CC ee GG Pp arg. gold, f: AA CC EE GG pp a a A Aa Aa G GG GG p A Aa G GG p Pp Aa G G 2. Fill in the squares GG P p Pp pp pp 3. Calculate the probabilities
Genetics 101 P 1: nutmeg, m: aa CC ee GG Pp arg. Gold, f: AA CC EE GG pp 3. Calculate the probabilities a a 4. Summarize stats G G P p A Aa Aa G GG GG p Pp pp A Aa G GG p Aa AA: 0/4 = 0% Aa: 4/4 = 100% aa: 0/4 = 0% GG GG: 4/4 =100% Gg: 0/4 = 0% gg: 0/4 = 0% Pp pp PP: 0/4 = 0% Pp: 2/4 = 50% pp: 2/4 = 50%
Genetics 101 4. Summarize stats AA: 0/4 = 0% Aa: 4/4 = 100% aa: 0/4 = 0% GG: 4/4 =100% Gg: 0/4 = 0% gg: 0/4 = 0% PP: 0/4 = 0% Pp: 2/4 = 50% pp: 2/4 = 50% Aa GG Pp 50% Aa GG pp 50% Therefore: Aa. GGPp 50% Non-self, gold, dark-eyed Aa. GGpp 50% Non-self, gold, pink-eyed
Genetics 101 Parents: aa CC ee GG Pp sp[+] Nutmeg AACC EEGG pp Spsp[+] Argente Golden, sp One of the parents is spotted: 1/2 of the offspring are spotted. /// Probabilities at the different loci: _A_ ___C_ ____E__ __G___ ____P_______ 1. 00 Aa 1. 00 CC 1. 00 Ee 1. 00 GG 0. 50 Pp 0. 50 pp /// Probabilities of the 2 colour(s): 0. 5000 Aa CC Ee GG Pp Golden Agouti 0. 5000 Aa CC Ee GG pp Argente Golden
Genetics 101 Good work!. . Let’s expand to six loci!
Genetics 101 The mother and father each have a pair of alleles on six loci : A -- controls the color of the belly A C – controls coat pattern; can lighten or colorpoint (darker extremities) E -- controls the amount of yellow G -- controls the amount of gold grey P -- controls eye color/coat intensity Sp -- controls spotting Sp
Genetics Don’t write anything 101 down yet…just follow along… We’ll need 6 Punnett Squares… 1. Fill in the parents and filial squares: black, m: aa Cc(b) Ee GG Pp spsp slate, f: aa Cc(h) Ee gg Pp spsp a aa aa C c(b) C CC Cc(b) E e E EE Ee a aa c(h) Cc(h) c(b)c(h) e g G G Gg P p P PP Pp g Gg p Pp pp Ee ee sp spsp spsp
Genetics 101 1. Calculate filial probabilities: black, m: aa Cc(b) Ee GG Pp slate, f: aa Cc(h) Ee gg Pp a aa aa C c(b) C CC Cc(b) E e E EE Ee a aa c(h) Cc(h) c(b)c(h) e AA: 0/4 = 0% Aa: 0/4 = 0% aa: 4/4 = 100% CC: 1/4 = 25% Cc(b): 1/4 = 25% Cc(h): 1/4 = 25% c(b)c(h): 1/4 = 25% Ee ee EE: 1/4 = 25% Ee: 2/4 = 50% ee: 1/4 = 25%
Genetics 101 Summarize stats AA: 0/4 = 0% Aa: 0/4 = 0% aa: 4/4 = 100% aa 100% CC: 1/4 = 25% Cc(b): 1/4 = 25% Cc(h): 1/4 = 25% c(b)c(h): 1/4 = 25% CC Cc(b) Cc(h) c(b)c(h) EE: 1/4 = 25% Ee: 2/4 = 50% ee: 1/4 = 25% EE ee 25% Ee 50% Therefore? There seems to be a lot of variety… why is this so? …what aspect of the parents led to such possibilities? …(let’s finish the other three loci)
Genetics 101 1. Calculate filial probabilities: black, m: aa Cc(b) Ee GG Pp slate, f: aa Cc(h) Ee gg Pp g G G Gg Gg: 4/4 = 100% P P p PP Pp p Pp pp PP: 1/4 = 25% Pp: 2/4 = 50% pp: 1/4 = 25% sp spsp spsp: 4/4 = 100%
Genetics 101 Summarize stats Gg: 4/4 = 100% Gg PP: 1/4 = 25% Pp: 2/4 = 50% pp: 1/4 = 25% spsp: 4/4 = 100% PP pp 25% spsp 100% Pp 50% Therefore? Let’s view the data on all loci and generate a list of probable colours. . .
P 1 cross: results Genetics 101 A C aa 100% CC 25% Cc(b) 25% Cc(h) 25% c(b)c(h) 25 % E G EE 25% Gg 100% Ee 50% ee 25% P sp PP 25% spsp 100% Pp 50% pp 25% 12 Probable colors 0. 4219 aa C- E-Gg P- Black 0. 0156 aa CCee Ggpp Arg Nutmeg 0. 1406 aa c[b]c[h] E-Gg P- Siamese 0. 0156 aa Cc[h]ee Gg pp ? Lt Arg 0. 0938 aa C- ee Gg P- ? Nutmeg 0. 0625 aa c[b]c[h] -- Gg pp PEW 0. 0156 aa Cc[b] ee Gg pp unkn clr 0. 0469 aa CC E- Gg pp Lilac Overwhelmed? --this is rare… 0. 0469 aa CC ee Gg P- Nutmeg most are more straightforward 0. 0469 aa Cc[b] E- Gg pp Sapphire and predictable. . . 0. 0469 aa Cc[h] E- Gg pp Dove 0. 0469 aa c[b]c[h] ee Gg P- ? Lt Clrpt Nutmeg
Genetics 101 A derivative color chart
Genetics 101 A family tree ~ courtesy of www. Geocities/Tokyo
Spotted Siamese Female (front) Male (rear) F 1 gen. From cage 22 (black spotted/burmese couple)
Genetics 101 What then is the difference between a Spotted, Pied, or Patched gerbil? Spotted: usually take the form of a white tip to the nose, a white spot on the forehead, a larger white spot just behind the ears and also a white tip to the tail. (May have any combo of the former– must have the tailtip. )
Genetics 101 Pied: The simple answer is that any gerbil with more extensive white markings than “spotted” will be described as pied. These markings can be; v A white collar linking the white spot behind the head to the white chest patch. v. A white line joining all three "classic" head spots together. v. OR Irregular white markings on the rump or tail
Genetics 101 Because these markings vary so much I have heard different names for different types of pied. For example, gerbils with just the line are called Striped and those with just the collar, Collared. Gerbils with both the line and the collar have been called Dutch due to the resemblance to mice and rabbits of that name. Gerbils with the irregular markings are called Variegated, Mottled, or Patched.
Genetics 101 Which is which? At this point we will simply refer to gerbils with additional markings as “spotted” or “pied”. Pied ? Spotted ? Patched ?
Genetics 101 Spotted, pied, or mottled? pied patched spotted
Spotted Siamese Female (front) Male (rear) F 1 gen. From cage 22 (black spotted/burmese couple)
c Cage 1(’ 04 -’ 05) d siblings Siamese spotted; male aac(b)c(h)EEGGPp Spsp+ dad Siamese spotted; female aac(b)c(h)EEGGPp Spsp+ Cage 22 parents mom
Genetics 101 We’ll need 6 Punnett Squares… 1. Fill in the parents and filial squares: sp siam, m: aa c(b)c(h) EE GG Pp sp siam, f: aa c(b)c(h) EE GG Pp c(b) c(h) a aa aa c(b)c(b)c(h) E EE EE a aa c(h) c(b)c(h) E EE G G G GG GG P p P PP Pp p Pp pp Sp sp Sp. Sp Spsp spsp
Genetics 101 1. Fill in the parents and filial squares: sp siam, m: aa c(b)c(h) EE GG Pp sp siam, f: aa c(b)c(h) EE GG Pp a aa aa c(b) c(h) c(b)c(b)c(h) E EE EE a aa c(h) c(b)c(h) E EE aa: 4/4 = 100% c(b): 1/4 = 25% c(b)c(h): 2/4 = 50% c(h): 1/4 = 25% EE: 4/4 = 100%
Genetics 101 1. Fill in the parents and filial squares: sp siam, m: aa c(b)c(h) EE GG Pp sp siam, f: aa c(b)c(h) EE GG Pp G GG GG: 4/4 = 100% P P p PP Pp p Pp pp PP: 1/4 = 25% Pp: 2/4 = 50% pp: 1/4 = 25% Sp sp Sp. Sp Spsp spsp Sp. Sp: ¼ = 25% Spsp: 2/4 = 50% spsp: ¼ = 25%
P 1 cross: results Genetics 101 A C E G aa 100% c(b) 25% EE 100% GG 100% c(b)c(h) 50% c(h) 25% P sp PP 25% Sp. Sp 25% Pp 50% Spsp 50% pp 25% spsp 25% Now list the probabilities at each locus. . . (see above)
P 1 cross: results Genetics 101 A C E G aa 100% c(b) 25% EE 100% GG 100% c(b)c(h) 50% c(h) 25% P sp PP 25% Sp. Sp 25% Pp 50% Spsp 50% pp 25% spsp 25% Probable colors: Now configure & calculate the rest of the genotypes… poss. Genotypes Phenotype Frequency aa c(b) EE GG PP Burmese 6. 25% aa c(b) EE GG Pp Burmese 12. 5% aa c(b) EE GG pp PEW (Pink Eyed White) 6. 25% 1. Calculate each percentage: aa c(b)c(h) EE GG PP Siamese 12. 5% aa c(b)c(h) EE GG Pp Siamese 2. Identify the color 25% A% x C% x E% x G% x P% = % for that genotype aa c(b)c(h) EE GG pp PEW 12. 5% aa c(h) EE GG PP 6. 25% = burmese Eg. aa c(b) EE GG PPDTW (Dark-Tailed White) aa c(h) EE GG Pp DTW 12. 5% 1 x. 25 x 1 x. 25 = 0. 0625 = 6. 25% aa c(h) EE GG pp PEW 6. 25%
P 1 cross: results Genetics 101 A C E G aa 100% c(b) 25% EE 100% GG 100% c(b)c(h) 50% c(h) 25% P sp PP 25% Sp. Sp 25% Pp 50% Spsp 50% pp 25% spsp 25% Distribution of 9 gene combinations over the colours: poss. Genotypes aa c(b) EE GG PP aa c(b) EE GG Pp aa c(b) EE GG pp aa c(b)c(h) EE GG PP aa c(b)c(h) EE GG Pp aa c(b)c(h) EE GG pp aa c(h) EE GG PP aa c(h) EE GG Pp aa c(h) EE GG pp Phenotype Frequency Burmese 6. 25% Burmese 12. 5% PEW (Pink Eyed White) 6. 25% Siamese 12. 5% Siamese 25% PEW 12. 5% DTW (Dark-Tailed White) 6. 25% DTW 12. 5% PEW 6. 25%
Genetics. What about the 101 spotted locus? P 1 cross: results poss. Genotypes Phenotype Frequency aa c(b) EE GG PP Burmese aa c(b) EE GG Pp Burmese aa c(b) EE GG pp PEW aa c(b)c(h) EE GG PP Siamese aa c(b)c(h) EE GG Pp Siamese aa c(b)c(h) EE GG pp PEW aa c(h) EE GG PP DTW aa c(h) EE GG Pp DTW aa c(h) EE GG pp PEW 6. 25% 12. 5% 6. 25% Results 18. 75% 37. 5% 18. 75% 25% 4 Probable colors 37. 5% aa c[b]c[h] EE GG P- Siamese 25% aa c-c- EE GG pp Pink Eyed White (PEW) 18. 75% aa c[b] EE GG P- Burmese 18. 75% aa c[h] EE GG P- Dark Tailed White (DTW) Both parents are spotted: 1/4 of the offspring die before birth. Of the rest 2/3 are spotted
Genetics 101 The lethal gene… Sp sp Sp Spsp sp Spsp spsp ¼ Sp. Sp : 25% lethal Note: the “spotted gene” is a lethal 1/4 gene… when present it trims down (carrier dies in utero) the litter to 3/4 its normal size and ½ Spsp : 50% spotted guarantees that 2/3 of the (remaining 66% or 2/3) remaining ones are spotted. Here’s how… ¼ spsp: 25% unspotted 3/4 (remaining 33% or 1/3) *do not include this locus in your colour probability list…simply state the case: eg: “Both parents are spotted: 1/4 of the offspring die before birth. Of the rest 2/3 are spotted. ”
Genetics 101 Now that you’ve plunged into it this far… Are you ready to figure out another family tree probability?
Genetics 101 ’ 04 -’ 05 Cage 16 Now take some time to master the following steps to arrive at a probable colour list… nutmeg; m argente cream; f aa. CCee. GGPp Aa. Cc(h)EEGGpp
Genetics 101 STEPS to determine the genotypic probability of offspring 1. write down your "cross" (mating) 2. draw 6 Punnett squares 3. "split" the letters of the genotype for each parent & put them "outside" the squares 4. determine the possible genotypes of the offspring by filling the squares 5. summarize percentages for each locus 6. calculate & list results (genotypes, phenotypes, percentages) 7. Summarize list of probable colors from highest percentage to lowest percentage.
Genetics 101 We’ll need 5 Punnett Squares… 1. Fill in the parents and filial squares: nutmeg, m: aa CC ee GG Pp arg. crm, f: Aa Cc(h) EEGG pp a a A Aa C C C CC e e E Ee a c(h) Cc(h) E Ee aa aa G GG GG P p p Pp pp G GG GG p Pp pp Note: if both parents are unspotted (spsp), don’t bother with the sixth P-square.
P 1 cross: results A C Genetics 101 E G P sp 0. 50 Aa 0. 50 CC 1. 00 Ee 1. 00 GG 0. 50 Pp 1. 00 sp[+] phenotypes 0. 50 aa 0. 50 Cc[h] Aa CC Ee GG Pp Golden agouti percentages 0. 50 pp. 5 x 1 x. 5 =. 125 25% Aa CC Ee GG pp Argente golden . 5 x 1 x. 5 =. 125 Aa Cc(h) Ee GG Pp Golden agouti . 5 x 1 x. 5 =. 125 Aa Cc(h) Ee GG pp Argente cream . 5 x 1 x. 5 =. 125 aa CC Ee GG Pp Black . 5 x 1 x. 5 =. 125 aa CC Ee GG pp Lilac aa Cc(h) Ee GG Pp Black . 5 x 1 x. 5 =. 125 aa Cc(h) Ee GG pp Dove . 5 x 1 x. 5 =. 125 25% . 5 x 1 x. 5 =. 125
Genetics 101 Cage 16 Nutmeg aa. CCee. GGPp male Argente Cream Aa. Cc(h)EEGGpp female Filial probability (6 probable colours): 25% Aa. C-Ee. GGPp golden agouti 25% aa. C-Ee. GGPp black 12. 5% Aa. CCEe. GGpp argente golden 12. 5% Aa. Cc(h)Ee. GGpp argente cream 12. 5% aa. CCEe. GGpp 12. 5% aa. Cc(h)Ee. GGpp dove lilac
Genetics 101 We’ll need 5 Punnett Squares… 1. Fill in the parents and filial squares: black, m: aa CC EE Gg Pp x black, f: aa CC EE Gg Pp a aa aa C CC CC E EE EE a aa C CC E EE G g G GG Gg P p P PP Pp g p Pp pp Gg gg Note: both parents are unspotted (spsp), don’t bother with the sixth Psquare.
P 1 cross: results Genetics 101 A C E G P 1. 00 aa 1. 00 CC 1. 00 EE 0. 25 GG 0. 25 PP 0. 50 Gg 0. 50 Pp 0. 25 gg 0. 25 pp phenotypes percentages aa CC EE GG PP Black . 25 x. 25 =. 0625 aa CC EE GG Pp Black . 25 x. 5 =. 125 aa CC EE GG pp Lilac . 25 x. 25 =. 0625 aa CC EE Gg PP Black . 5 x. 25 =. 125 aa CC EE Gg Pp Black . 5 x. 5 =. 25 aa CC EE Gg pp Lilac . 5 x. 25 =. 125 aa CC EE gg PP Slate . 25 x. 25 =. 0625 aa CC EE gg Pp Slate . 25 x. 5 =. 125 aa CC EE gg pp Ruby-Eyed White . 25 x. 25 =. 0625 56. 25% 18. 75% 6. 25%
Genetics 101 black aa CC EE Gg Pp male black aa CC EE Gg Pp female Filial probability (4 probable colours): 56. 25% aa. CCEEG-P- black 18. 75% Aa. CCEegg. P- slate 18. 75% aa. CCEEGgpp lilac 6. 25% aa. CCEEggpp BEW
Genetics 101 Some odds & ends so as to leave this work unfinished. . . "Unfinished Portrait of George Washington" Gilbert Stewart
Genetics 101 • You will now suffer a quiz… May the Force be with you… And thereafter? … An examination !
Genetics 101 the end