Patterns of Heredity

KaryotypePicture of chromosomes arranged

in homologous pairs.#1-22 called autosomes#23 called sex chromosomes

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 peakFree hanging ear lobes(attached)Huntington’ Disease-

slow ,progressive neurological disease that appears after age 35-become incapacitated. Loss of muscle and motor control.

SEX DETERMINATIONpair #23- sex chromosomesxx= femalexy= 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.

Nondisjunctionchromosomes fail to separate

during meiosis. Ex. Down’s Syndrome- trisomy 21 extra #21

chromosome

Sex linked traitsCarried on the X chromosomeMostly males affected because

they have only 1 X chromosomeColorblindnessHemophilia-no clotting factor

XHXh- Female carrierXhY- Male affectedXhXh- Female affected

Complex Inheritance TraitsSickle cell anemia- common to black African

AmericansHemoglobin doesn’t bind to O2

properlyCells are sickle shapedClot easilyHomozygous(ss) have diseaseHeterozygous(Ss) show some

traits

Blood groups4 blood types-A, B, AB, O3 alleles- IA,IB,i

Type O is universal donor-no marker on cell(generic)

Type AB- universal recipient- no antibodies in serum

TYPE GENOTYPE

On cells In serum

A IAIA/IAi A Anti Bantibodies

B IBIB/IBi B Anti A antibodies

AB IAIB A and B Nothing

O ii Nothing Anti A antibodies

Anti B antibodies