GENETIC PRINCIPLES

Lounging around the house Two heads are better than one Look before you leap

GENETIC PRINCIPLES If the genes are on the same chromosome, they will not follow the law of Independent Assortment. Polygenic Inheritance: When more than one gene affects the phenotype of a trait. Target: I will be able to identify the phenotype given a genotype in incomplete dominance, co-dominance, and multiple alleles. Pg. 33

Exceptions to Simple Dominance: 1. Incomplete Dominance: when the two alleles in a heterozygous genotype contribute to the individual phenotype that isn’t like either parent  Neither allele is completely dominant; there is a blend of the two. R WWWW RW Genotype Ratio: 4 (100%) RW Phenotype Ratio: 4 (100%) Pink

2. Co-Dominance: When two dominant alleles are expressed at the same time  Represented in Punnett squares by capital letters with superscripts- ex: C B, C W. C B CWCWCWCW C B C W Genotype Ratio: 4 (100%) C B C W Phenotype Ratio: 4 (100%) black and white (C B, C W ) C B C W

3. Multiple Alleles: When there are more than two alleles for a trait Ex: There are three types of blood alleles in humans- A, B, and O  A and B are Dominant over O  O is Recessive  A and B are Co-Dominant CaucasiansAfrican American HispanicAsian O +37%47%53%39% O -8%4% 1% A +33%24%29%27% A -7%2% 0.5% B +9%18%9%25% B -2%1% 0.4% AB + 3%4%2%7% AB -1%0.3%0.2%0.1%

Human Blood Types Summary: GenotypeBlood Type (Phenotype) A I B I B or I B i B iiO I A I B AB I A i IA IBIA IB I A I A or I A i I A I A i I A I B I B i Genotype Ratio: 1 I A I A : 1I A i : I A I B : I B I Phenotype Ratio: 2 Type A: 1 Type AB: 1 Type B

WHEN MENDEL WAS WRONG Divide paper into 3 sections. Draw pictures to represent Incomplete Dominance, Co-Dominance, and Multiple Alleles *Use a minimum of 4 colors Pg. 32