GENETIC PRINCIPLES. Lounging around the house Two heads are better than one Look before you leap.
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Transcript of GENETIC PRINCIPLES. Lounging around the house Two heads are better than one Look before you leap.
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
RW
W
RW RW
RW 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: CB, CW.
CB CB
CW
CW
CB
CW
Genotype Ratio: 4 (100%) CBCW
Phenotype Ratio: 4 (100%) black and white (CB, CW)
CB
CW
CB
CW
CB
CW
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 OO is RecessiveA and B are Co-Dominant
Caucasians African American
Hispanic Asian
O +
37% 47% 53% 39%
O - 8% 4% 4% 1%
A + 33% 24% 29% 27%
A - 7% 2% 2% 0.5%
B + 9% 18% 9% 25%
B - 2% 1% 1% 0.4%
AB +
3% 4% 2% 7%
AB -
1% 0.3% 0.2% 0.1%
Human Blood Types
Summary:
Genotype Blood Type (Phenotype)A
IB IB or IB i
Bii OIA IB AB
IA
iIA
IB
IA IA or IA i
IA IA
IA i
IA IB
IB i
Genotype Ratio: 1 IA IA : 1IA i : IA I B : IB 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