INCOMPLETE DOMINANCE n With incomplete dominance a cross
- Slides: 56
INCOMPLETE DOMINANCE n With incomplete dominance, a cross between organisms with two different phenotypes produces offspring with a third phenotype that is a blending of the parental traits.
INCOMPLETE DOMINANCE When the phenotype of the heterozygous is intermediate between the two homozygous n Neither allele is dominant/recessive over the other. Neither allele will express itself---therefore NO capital or lower case letters n
INCOMPLETE DOMINANCE n n EX: Snapdragon flowers. Red flowers White flowers Pink Flowers n n When working these problems it becomes essential to make a key Red (RR) White (WW) Pink (RW)
INCOMPLETE DOMINANCE Cross a Red Snapdragon flower with a White Snapdragon flower. n Set up the Punnett Square and give me both pheno and geno Ratios. n
INCOMPLETE DOMINANCE
INCOMPLETE DOMINANCE n Phenotypic Ratio 100% Pink n Genotypic Ratio 100% RW
INCOMPLETE DOMINANCE n You cross two pink flowers and give me both phenotypic and genotypic ratios.
CO-DOMINANT ALLELES n n Where both alleles express themselves fully. With Co-dominance, a cross between organisms with two different phenotypes produces offspring with a third phenotype. This third phenotype has BOTH parental traits expressed.
CO-DOMINANT ALLELES n n This is most commonly seen in chickens. Cross a black chicken with a white chicken you get what is called a speckled chicken NOT GRAY…but both alleles (black and white) fully express themselves so the chicken has both types of feathers.
CO-DOMINANT ALLELES n White cow crossed with a Red Bull
CO-DOMINANT ALLELES Roan Cow…. Roan refers to cows that have red coats with white blotches.
CO-DOMINANT ALLELES A white horse crossed with a black stallion
CO-DOMINANT ALLELES A gray horse…but upon closer inspection it has hairs that are both black and hairs that are white.
POLYGENIC TRAITS More than one allele pair controls a single trait— n Ex: Skin Color—Several different allele pairs attribute to the overall phenotype— Tone, distribution, etc n
MULTIPLE ALLELES n n A population might have more than two alleles for a given gene. In this case you have to think of a gene as a segment of your DNA that controls a trait. You have more than 2 choices for an allele for each trait. Even if more than two alleles exist in a population, any given individual can have no more than two of them.
MULTIPLE ALLELES n Ex: Blood type, Rabbit Fur, Labrador Retriever Coat Color
MULTIPLE ALLELES n In Labs, coat color is determined by one gene with four different alleles. Five different colors result from a combination of these alleles.
Phenotype Possible Genotypes BBEE Bb. EE BBEe Bb. Ee bb. EE bb. Ee BBee Bbee bbee
Multiple Alleles- Blood Type of Preferred Permissible Recipient Blood Type of Donor A A A, O B B B, O AB AB AB, A, B, O O
Multiple Alleles- Blood Type
Multiple Alleles-Rabbit Fur n n Coat color in rabbits is determined by a single allele pair that has at least four different alleles. Full(C), Chinchilla (Ch), Himalayan (h), Albino (c)
SEX CHROMOSOMES n We already know that each human has 46 chromosomes which means they have 23 homologous pairs. n The 23 rd Pair is different. It determines the sex of the individual.
SEX CHROMOSOMES n Homologous Pairs 1 -22 are called Autosomes n The 23 pair often called the Sex Chromosome.
FEMALE SEX CHROMSOMES n Female 23 rd Chromosome is represented by XX.
MALE SEX CHROMSOMES n The 23 Chromosome on the male is represented with a XY.
SEX-LINKED TRAITS n Genes that are carried by either sex chromosome are said to be Sex-linked Traits.
SEX-LINKED TRAITS n Scientist discovered this linkage when studying fruit flies (Drosophilia). Through many experiments scientist soon concluded eye color of these flies were determined by the sex chromosome.
SEX-LINKED TRAITS n Often an allele for a trait can be found on the X but not on the Y chromosome. n The Y chromosome on the male carries little or NO genetic information.
SEX-LINKED TRAITS n n n WHEN WORKING ANY SEXLINKED TRAIT YOU MUST ALWAYS WRITE IT OUT…… XX x XY You still have dominant and recessive alleles.
SEX-LINKED TRAITS n n Eye color in fruit flies is a sex-linked trait where Red eyes is dominant over White eyes. (This trait is carried on the X chromosome) Cross a heterozygous Red eyed female with a red eyed male.
SEX-LINKED TRAITS Practice Problems n n Cross a heterozygous Red eyed female with a red eyed male. Cross a homozygous Red eyed female with a white eyed male. Allow the F 1 generation male/female to cross. Show me Cross, Punnett Square, and Phenotypic and Genotypic Ratio
SEX-LINKED TRAITS n Most sex-linked traits are carried on the X chromosome. Therefore the female will carry two and the male will only carry one. n However, some sex-linked traits are carried on the Y…but only a few!!
SEX-LINKED TRAITS Colorblindness n Hemophilia n Duchenne Muscular Dystrophy n Fragile X Syndrom n
SEX-INFLUENCED TRAITS n n n (NOT located on X or Y chromosome)found in both sexes but expressed differently. Baldness-caused by autosomal allele that is dominant in men due to the presence of testosterone. It is recessive trait in women. Index finger length- Dom/fem Rec/Mal
SEX-LIMITED TRAITS Sex-limited traits are autosomal traits that are expressed in only one sex (In normal conditions) n Ex: Breast, Beards, Breast milk. n
TESTCROSS n Testcross- one way to determine the genotype of an unknown genotype is to cross it with a known genotype (usually recessive)
TESTCROSS n A breeder is considering using this dog to produce offspring. However the owner is unsure if the dog is a possible carrier of a common hearing problem. She knows that he has normal hearing. What can she do?
Carrier n A carrier is a heterozygous individual. They do NOT have the trait but do have the possibility to pass it to their offspring. Dd
TESTCROSS n When performing a test cross you would cross the unknown genotype with a known…usually a homozygous recessive. n Many breeders will rely on a testcross to determine if they are dealing with a pure breed or a hybrid.
PEDIGREE n A graphic representation of an individuals family tree.
KAROTYPE n n n A photograph that shows an individuals chromosomes in homologous pairs. Usually done by collecting white blood cells-stimulating mitosis and capture the information. Karotype can be used to find any chromosomal abnormality.
KAROTYPE n n Most abnormalities are called by Nondisjuction- the failure of one or more chromosomes pairs to separate during meiosis. Down Syndrome Klinefelter Syndrome Turner Syndrome
- Punnett square example
- Incomplete dominance
- Codominance example
- Chapter 12 lesson 2 applying mendels principles
- Incomplete dominance punnett square
- Incomplete dominance pedigree
- Co dominance with example
- Harry potter genetics incomplete dominance answer key
- Incomplete dominance definition
- Codominance
- Co dominance with example
- Incomplete dominance punnett square
- Incomplete dominance
- Dog
- An example for incomplete dominance
- Pea plant flower color
- In incomplete dominance
- Incomplete dominance example
- Baby skin colour predictor
- What does yellow and blue make
- Mendelian genetics definition
- Incomplete dominance in snapdragons
- Incomplete dominance
- Incomplete dominance
- Incomplete dominance
- Incomplete dominance definition
- Codominance in horses
- Suit separate
- Andalusian chicken incomplete dominance
- Incomplete vs codominance
- Whats the difference between dominance and codominance
- Codominance definition
- Incomplete dominance occurs when
- Whats incomplete dominance
- Cross dominance
- Test cross and back cross with example
- What is the difference between monohybrid and dihybrid
- In the cross, in the cross be my glory ever
- Test cross and back cross
- Condylar guidance
- Co dominance
- Define imperialism
- Types of dominance in art
- Examples of co dominance
- Ggrr x ggrr
- Center for information dominance
- Dominance in art definition
- Standards battles and design dominance
- Apical dominance
- Mendel's law of dominance
- Degrees of dominance
- Dominance hiearchy
- Complete dominance pattern of inheritance
- "blackburn college"
- Asymmetric dominance effect
- Dominance structuring examples
- Emotive style communication