(Where did you get your genes?) Types of Dominance (Where did you get your genes?)

Incomplete Dominance Neither trait is dominant over the over Principle of Dominance does NOT apply! Hybrid phenotype looks “in between” the two homozygous phenotypes

F2 Generation

Types of Dominance Incomplete Dominance genotype: heterozygous (hybrid) phenotype: the mix or “in between” of the two parents example: white flower x red flower  pink flowers

Codominance Neither trait is dominant over the over Principle of Dominance does NOT apply! Hybrid genotype displays phenotype where both P generation phenotypes can be seen

BB x WW

F1 cross (BW x BW)

TYPES OF DOMINANCE Codominance offspring does not look like either parent both alleles in the offspring are dominant example: black cow x white cow  checkered (roan) cow

Multiple Alleles More than two allele possibilities exist Ex: blood type A, B, O

Multiple Alleles More than two allele possibilities exist

Dad = type A blood Mom = type B blood A & B are codominant A & B are both dominant over O

blood type determined by the presence or absence of proteins on the surface of red blood cells types: A, B, AB, O

Antigen on red blood cell BLOOD TYPES Phenotype (blood type) Genotype Antigen on red blood cell Safe Transfusions To From A AA or AO A, AB A,O B BB or BO B, AB B, O AB only AB A and B A, B, AB, O O only O none

Polygenic traits

Sex-linked traits 23 pairs of chromosomes 46 total 1st 22 pairs = “autosomes” 23d pair = sex chromosomes XX = female XY = male X & Y = “sex chromosomes”

Karyotype A picture of an organism’s chromosomes Can be used to determine if there are genetic abnormalities

SEX-LINKED TRAITS controlled by genes located on sex chromosomes usually found on the X (female) chromosome female are usually carriers because they have XX for X-linked traits, males pass the trait to their daughters not their sons…why? examples: colorblindness, hemophilia

H = does not have hemophilia h = hemophilia Xh Y XH Xh