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Patterns of Heredity. Karyotype. Picture of chromosomes arranged in homologous pairs. #1-22 called autosomes #23 called sex chromosomes. Pedigree-graphic representation of a family’s genetic history. Simple Recessive Diseases (little,little).
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Karyotype • Picture of chromosomes arranged in homologous pairs. • #1-22 called autosomes • #23 called sex chromosomes
Pedigree-graphic representation of a family’s genetic history
Simple Recessive Diseases(little,little) • Tay Sachs-missing enzyme that metabolizes fats. Fats accumulate in brain. Fatal • Cystic Fibrosis- excessive mucous production in the lungs.”Drown” in own fluid • Phenylketonuria-(PKU)- body can’t metabolize phenylalanine into tyrosine –Phenylalanine accumulates. Monitor intake amount.
Simple Dominant Traits(Big,Big or Big,little) • Widows peak • Free hanging ear lobes(attached) • Huntington’ Disease- slow ,progressive neurological disease that appears after age 35-become incapacitated. Loss of muscle and motor control.
SEX DETERMINATION • pair #23- sex chromosomes • xx= female • xy= male
Sex Chromosome Disorders • X0- Turners Syndrome-female who is sterile • XXY- Klinfelter’s Syndrome- males with an extra X.Sterile. • No baby has been born without an X-vital for embryonic survival. With no Y, baby is female. Y chromosome contains sex determining region that causes male sexual development.
Nondisjunction • chromosomes fail to separate during meiosis. Ex. Down’s Syndrome- trisomy 21 extra #21 chromosome
Sex linked traits • Carried on the X chromosome • Mostly males affected because they have only 1 X chromosome • Colorblindness • Hemophilia-no clotting factor • XHXh- Female carrier • XhY- Male affected • XhXh-Female affected
Complex Inheritance Traits • Sickle cell anemia- • common to black African Americans • Hemoglobin doesn’t bind to O2 properly • Cells are sickle shaped • Clot easily • Homozygous(ss) have disease • Heterozygous(Ss) show some traits
Blood groups • 4 blood types-A, B, AB, O • 3 alleles- IA,IB,i • Type O is universal donor-no marker on cell(generic) • Type AB- universal recipient- no antibodies in serum