- Slides: 86
The Human Genome Chapter 14 -1 & 14 -2
A _____ is a picture of an organism’s chromosomes
Chromosomes that determine the sex of an organism = _________ http: //www. angelbabygifts. com/ All other chromosomes = _________ Humans have two sex chromosomes and _____ autosomes
SEX DETERMINATION XX = _____ Xy = ______ Y is only chromosome without a true homologous partner
Who decides? Mom can give X Dad can give X or y X XX XX y Xy Xy SO ____ determines sex of the baby. If dad gives X with mom’s X = girl If dad give y with mom’s X = boy
HUMAN GENETICS Dominant and Recessive Homozygous/Heterozygous work for human genes too!
REMEMBER YOUR MOLECULES! ____ are made by joining ______ subunits together
REMEMBER YOUR MOLECULES _____ is carried in the ____ of A, T, G, C’s on a _____ molecule
The sequence of A’s, T’s, G’s & C’s tells the _______ of ____ in the ____
Changes in the gene code ________ that is made A change in the genetic code = ________
Mutations can happen: • when cells make_____ in copying DNA • when cells are exposed to environmental ______ like _____- X-rays, tanning booths _____ - cigarette smoke, pollutants _____ - HPV
MUTATIONS can be: ______ - Mutations that produce _______ are usually harmful. Harmful mutations are associated with many ________ and can cause ______
MUTATIONS can be: ______Most mutations have little or no effect on gene ____. Proteins still work. Organism can still function. http: //photos. dataeast. free. fr/Flippers/dataeast/turtles/pub. jpg
MUTATIONS can be: ______ - Some mutations change proteins that are so vital to life that they cause death, usually before birth. 50% of pregnancies that abort spontaneously have genetic abnormalities http: //www. global-warming-and-the-climate. com/images/tombstone-RIP. gif
MUTATIONS can be: ______- Mutations are also a source of _______ in the population Mutations can help an organism _________ Provide a way for species to change over time MORE ON THIS 2 nd SEMESTER!
KINDS OF MUTATIONS ____ CELLS = ______ CELLS Somatic cell mutations can: Cause ______ Make cell ____ able to _____ cell v. BUT _____ passed on to offspring
Kinds of Mutations ______ = _____cells (sperm & eggs) v Germ cell mutations ____ passed on to offspring http: //anthro. palomar. edu/biobasis/images/meiosis. gif
Images from: http: //www. bbc. co. uk/scotland/education/bitesize/higher/img/biology/genetics_adaptation/mutations/02 gene_mutation. gif KINDS OF MUTATIONS Mutations that produce changes in a single gene = _________ Mutations that produce changes in whole chromosomes = ___________
MUTATIONS can be: Mutations that happen to genes on autosomes are called ______ Mutations that happen to genes on X or y chromosomes are called ________
MANY HUMAN GENES HAVE BECOME KNOWN THROUGH THE STUDY OF GENETIC DISORDERS Many genetic ______ result from changes in the DNA code so that _________which are produced don’t _______ correctly. http: //patentdocs. typepad. com/photos/uncategorized/2007/05/28/dna 1. gif
REMEMBER: MANY PROTEINS ARE ENZYMES THAT HELP CHEMICAL REACTIONS HAPPEN! IF ENZYME DOESN’T WORK, CELL CAN’T DO SOMETHING IT NEEDS TO DO http: //www. biologie. uni-hamburg. de/b-online/library/cat-removed/enzyme_. gif
A mutation that causes a protein to NOT WORK would appear ________ to the normal working allele. ______________ is an example of an _____________ GENETIC DISORDER
Phenylketonuria (PKU) CAUSE: Mutation in gene for an ______ that _____ an ______ called phenylalanine Build up causes ____________ http: //biology. clc. uc. edu/courses/bio 104/protein. htm
Phenylketonuria (PKU) ____ babies are ____ for PKU before they leave the hospital. http: //labspace. open. ac. uk/file. php/2588/SK 195_6_002 i. jpg Treatment: Need a diet ___________ to extend life and _______ mental retardation If phenylalanine is an _______, what type of foods should PKU patients avoid? _________
REAL WORLD LINK What does a can of Diet Coke have to do with human genetics? LOOK AT THE WARNING LABEL ! _______ is made with phenylalanine
heterozygous person A _____ who carries a recessive allele for a _____ genetic disorder, but doesn’t show _______ the disorder themselves is called a CARRIER _______ http: //www. biochem. arizona. edu/classes/bioc 460/spring/rlm/RLM 36. 1. html
A mutation that codes for a new protein whose action masks the normal allele appears as a _______ mutation. __________ is an example of a _____________ GENETIC DISORDER
THINK ABOUT IT Click to hear Woody’s song What does the song have to do with human genetics? “This Land is My Land” was written by a musician named Woody Guthrie before he began to show the symptoms of Huntington’s disease.
HUNTINGTON’S DISEASE CAUSE: _______ of an extra 40 -100 ______ at end of gene on chromosome 4 The _______. . . the earlier it shows up and more _____ the symptoms. http: //www. healthsystem. virginia. edu/internet/huntdisease/images/cag. gif
HUNTINGTON’S DISEASE Huntington’s brain Appears at ______ Lose the ability to walk, talk, feed yourself, and other ____ functions 1 in 10, 000 people in U. S. have Huntington’s disease Normal brain http: //www. scielo. br/img/revistas/bjmbr/v 39 n 8/html/6233 i 01. htm
A person with Huntington’s disease has a _____ chance of passing the disorder on to their offspring. Problem: Symptoms of disorder usually don’t show until ______. . . so you don’t know you have it until ____ you have had children.
Woody Guthrie had a son named Arlo that was a popular musician during the 70’s Click to hear one of Arlo’s songs Before 1993 there was no test for Huntington’s. If one of your parents showed symptoms, you had to wait to see if it had been passed on to you.
http: //www. jimdirden. com/woodyfest 2004/artists/index_3. htm Arlo Guthrie is still performing today. He never developed symptoms for Huntington’s disease. If there is NO cure, would YOU want to be tested and find out if you have the gene? http: //webs. wichita. edu/depttoolsmemberfiles/accomp/question_mark%20(Win. CE). jpg
SEX CHROMOSOMES CAN CARRY OTHER GENES TOO = __________ These traits show up in different ________ in males and females because they move with the sex chromosomes
Y-LINKED GENES: Genes _______ chromosome EXAMPLE: Hairy pinna _____genes _____ show up _______
______ GENES: are carried on the X chromosome X-linked recessive disorders show up _______ in ______ than females because males only have ______ X chromosome.
Males ONLY HAVE ONE X DEFECTIVE They either have the disorder NORMAL Or They are normal
FEMALES HAVE TWO X CHROMOSOMES NORMAL DEFECTIVE Females have one normal gene that works. DEFECTIVE Females _____ defective recessive alleles to show the disorder
The X chromosome in males. . . flies WITHOUT a copilot!. . . there’s NO BACK UP X to help them!
COLORBLINDNESS CAUSE: Mutation in one of three genes for ________ carried on X chromosome Persons with this disorder have trouble distinguishing colors. _________ colorblindness is most common Seen in 10 males 1 in 100 females http: //gizmodo. com/gadgets/peripherals/samsung-develops-lcd-for-colorblind-036306. php
________ Abnormalities • 1 infant in 200 newborns has a chromosomal abnormality • 28% of first trimester miscarriages have a chromosomal abnormality • Abnormalities in larger chromosomes don’t usually survive
______________: Change in the _______ or ______ of chromosomes
Homologous chromosomes ________ during MEIOSIS = _____________ One cell gets 2 copies of the chromosome the other cell gets none.
Normal Meiosis Nondisjunction http: //web. udl. es/usuaris/e 4650869/docencia/gen_etica/meioferti 2. html http: //www. tokyo-med. ac. jp/genet/anm/domov. gif
Nondisjunction Since it happens to a sperm or egg, the new baby can end up with _______ of a chromosome = _________ OR only ______ of a chromosome = __________
Down syndrome (= ______)
AUTOSOMAL DOMINANT Examples of ____________ DISORDERS: HUNTINGTON’s __________ ACHONDROPLASIA __________
ACHONDROPLASIA (One kind of Dwarfism) AUTOSOMAL DOMINANT CAUSE: ______________ gene 1 in 20, 000 births 200, 000 “little people” worldwide One of oldest known disorders – seen in Egyptian art
ACHONDROPLASIA (One kind of Dwarfism) Normal size head and torso; short arms and legs Problem with way cartilage changes to bone as bones grow
DISORDERS CAUSED AUTOSOMAL CODOMINANT ALLELES BY __________ SICKLE CELL DISEASE __________ CAUSE: T changed to A in gene for HEMOGLOBIN _________ (protein in red blood cells that carries oxygen in blood)
SICKLE CELL DISEASE SYMPTOMS: RED BLOOD CELLS become sickle _______ TWO shaped in persons with ______ ALLELES sickle cell ____
SICKLE CELL DISEASE Circulatory problems Cells stick in capillaries Loss of blood cells (anemia) Organ damage (brain, heart, spleen) Can lead to DEATH
SICKLE CELL DISEASE AFRICAN AMERICANS More common in _________ 1 in 500 = have sickle cell disease 1 in 10 = carriers for allele MEDITERRANEAN Also affects persons of ________ MIDDLE EASTERN and _________ descent Why do so many African Americans carry the sickle cell allele?
SICKLE CELL DISEASE Many can trace their ancestry to west MALARIA central Africa where ______, a serious parasitic disease that infects red blood cells is common. Watch a video about sickle cell and malaria Images from: http: //en. wikipedia. org/wiki/Malaria
MUTATIONS REMEMBER: MUTATIONS CAN BE BENEFICIAL if they help an individual survive
A person who is _________ for HOMOZYGOUS the ______allele (ss) will have sickle cell ________ sickle disease HOMOZYGOUS A person who is _________ for normal hemoglobin alleles will have normal blood cells, but can become infected with malaria _____ (SS) HETEROZYGOUS person (Ss) A _________ (with one normal/one sickle cell allele) is generally healthy and has the benefit of resistant to malaria being _____
X-LINKED RECESSIVE Examples of ____________ DISORDERS: HEMOPHILIA __________ COLORBLINDNESS __________ DUCHENNE MUSCULAR DYSTROPHY __________
HEMOPHILIA CAUSE: Mutation in genes for _________ Blood clotting proteins on X chromosome carried ______ Blood clotting proteins are missing so person with this disorder can’t stop bleeding when bleed to death from minor injured; can ________ cuts or suffer internal bleeding from bruises or bumps.
HEMOPHILIA Treatment: injections of normal clotting Need ______ proteins to stop bleeding More common in ______ males because it is _______ TWO recessive X-linked, but females with ______ hemophilia alleles will also show the trait. 1 in 10, 000 males has hemophilia
Duchenne Muscular Dystrophy CAUSE: deletion in gene that codes for a muscle protein ________ Results in progressive weakening __________ and loss of skeletal muscle __________ http: //www. cadenhead. org/workbench/gems/jerry-lewis-telethon. jpg http: //www. tokyo-med. ac. jp/genet/chm/dei. gif
Duchenne Muscular Dystrophy (DMD) SYMPTOMS: 1 in 3000 male births Appears before age 5 Progressive muscle weakening Most in wheelchair by age 13 Eventually lethal
What’s the pattern: Y-linked traits show up _______ ONLY in _______ males ____ X-linked recessive traits: ______________________ more common in males than females. ________ ONLY FEMALES can be ____. carriers AUTOSOMAL RECESSIVE traits: ____________ FEMALES can be ____ carriers BOTH MALES ______ & _____
Human Abnormalities caused by Non-Disjunction _________ Down syndrome Klinefelter syndrome _________ Turner syndrome _________
TRISOMY 21 Down syndrome (= ______)
Down syndrome (Trisomy 21) • 1 in 800 births • Similar facial features • Slanted eyes • Protruding tongue
Down syndrome (Trisomy 21) Simian line on palm http: //www. medgadget. com/archives/img/simian. jpg
Down syndrome (Trisomy 21) • Most common chromosomal abnormality • 50% have heart defects that need surgery to repair • Mild to severe mental retardation • Increases susceptibility to many diseases • Risk of having a child with Down syndrome increases with age of mom
XO Turner syndrome ____ • • • 1 in 5000 births Females have only one X chromosome Small size Slightly decreased intelligence 35% have heart abnormalities Hearing loss common Broad chest Reproductive organs don’t develop at puberty Can’t have children http: //medgen. genetics. utah. edu/photographs/diseases/high/611. gif
Klinefelter syndrome XXy
Klinefelter syndrome • 1 in 1000 births • Males have extra X chromosomes (Can be XXy, XXXy, or XXXXy) • Average to slight decrease in intelligence • Small testes/can’t have children • Usually not discovered until puberty when don’t mature like peers
Karyotype (need cells from baby) Image from: http: //members. tripod. com/~yenial/chromosome. html Can tell _________ MISSING/EXTRA chromosomes GENDER _____ DELETIONS/INSERTIONS Some ___________ Can’t see ________ mutations single gene
If having extra chromosomes causes genetic problems, how come having two X chromosomes in females and one X in males is not a problem?
X-chromosome Inactivation ONE X chromosome In female cells ______ SWITCHED OFF is randomly ________ It condenses and forms a dense region in the nucleus called a BARR BODY _______ http: //fig. cox. miami. edu/~cmallery/150/gene/barr. htm
CAT COLOR http: //www. islandstrolling. com/mainland/peloponnes/photo/mystra_cat_white_orange_black. jpg In cats, a gene that controls the SPOT COLOR _______ is carried on the X chromosome __________ In some female cells the X with the allele for orange spots is switched off and in some cells the X with the allele for black spots is switched off, so cat has different colored spots. See a video
CAT COLOR http: //ascensionparish. net/forum/messages/14/2493. jpg Male cats have only _____ one X chromosome, so they can only have ______ one color of spots! THINK ABOUT IT? How many colors of spots could a male cat with Klinefelter syndrome have?
PEDIGREES ________are diagrams genes are passed that show are ______ in families on _____ over several generations
Drawing a pedigree chart
http: //www. beavton. k 12. or. us/sunset/academics/genetics. htm
http: //www. ikm. jmu. edu/Buttsjl/ISAT 493/Hemophilia/hemophiliaeurope. html
CYSTIC FIBROSIS CAUSE: Loss of 3 DNA bases in a gene for the protein Cl- ions _______ that transports _____ so salt balance is upset thick mucous Causes a build up of _________ in lungs and digestive organs Image from: BIOLOGY by Miller and Levine; Prentice Hall Publishing © 2006
REMEMBER TRANSPORT ION CHANNELS are membrane _______ proteins that make _____ tunnels through the bilayer for ____ ions to pass through (Na+, K+, Ca++, Cl-)
CYSTIC FIBROSIS http: //learn. genetics. utah. edu/content/disorders/whataregd/cf/index. html
CYSTIC FIBROSIS Leads to: _____ and _____ respiratory digestive complications, increased susceptibility to infections; Salty skin is a symptom “_____” Caucasians More common in ______ but can affect all races. 30, 000 people in U. S. have cystic fibrosis 1 in 31 people are carriers