ODDS ENDS Slide show by Kelly Riedell A
ODDS & ENDS Slide show by Kelly Riedell
A pedigree is a diagram that shows how a trait is passed in families over many generations
http: //www. beavton. k 12. or. us/sunset/academics/genetics. htm
HEMOPHILIA http: //www. ikm. jmu. edu/Buttsjl/ISAT 493/Hemophilia/hemophiliaeurope. html
Failure of homologous chromosomes to separate during MEIOSIS NONDISJUNCTION = _____________ 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
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
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
Phenylketonuria (PKU) Mutation in gene for an enzyme that breaks amino acid down an _____(phenylalanine) Build up in brain causes mental retardation ALL babies are tested for PKU before they leave the hospital. X X X PROTEINS Need a special diet low in _____to extend life and prevent mental retardation http: //biology. clc. uc. edu/courses/bio 104/protein. htm
THINK ABOUT IT So why put a warning label on “sugar free” foods? There’s not a lot of protein in Diet pop ! The artificial sugar Aspartame ) is made ( _____ with phenylalanine
SICKLE CELL ANEMIA AUTOSOMAL CODOMINANT Substitution A changed to T in gene for ______ HEMOGLOBIN (protein in red blood cells that carries oxygen in blood) • Circulatory problems • Cells stick in capillaries • Loss of blood cells (anemia) • Organ damage (brain, heart, spleen) • Can lead to DEATH
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 Why do so many African Americans carry the sickle cell allele? Why don’t these awful genetic disorders disappear from the population if having the disorder is can cause death?
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
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 ADVANTAGE resistant to malaria of being _____
Deleterious genes stay in the population because there is somebody that benefits ADVANTAGE = HETEROZYGOTE ______________ Normal hemoglobin may or may NOT die from malaria Sickle cell disease Twice as many people aren’t sick with sickle cell AND are protected from malaria
We are finding more and more links between disease resistance and genetic mutation. Ex: The cystic fibrosis gene protects the body against typhoid fever. Tay-Sachs gene seems to confer some resistance to tuberculosis. Changes in the vitamin D receptor increase resistance to tuberculosis but increase the susceptability to osteoporosis.
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