Dominant allele with recessive lethality (black) Dominant allele with recessive lethality

Dominant allele with recessive lethality 1 gene with 2 alleles we’ve seen 4 cases: Dominant allele with recessive lethality 1 AA : 2 Aa : 1 aa complete dom/rec dom dom rec incomplete dominance dom blend dom-rec rec codominant dom1 dom1+ dom2 dom2 recessive lethal (dom. marker) dead dom rec

IC. Genes with multiple alleles 1 Gene with 3 alleles IA & IB are co-dominant; i is recessive

IC. Genes with multiple alleles Hierarchy of dominance: C > cch > ch > c

IC. Genes with multiple alleles chinchilla cch

IC. Genes with multiple alleles chinchilla cch

IC. Genes with multiple alleles chinchilla cch himalayan ch

IC. Genes with multiple alleles Hierarchy of dominance: C > cch > ch > c

IC. Genes with multiple alleles

IC. Genes with multiple alleles A short list of the 1587 known mutant alleles of the Drosophila melanogaster eye color gene w (white)

ID. Two genes, interacting Back to 2 genes TIME

ID. Two genes, interacting

A/A ; B/B a/a ; b/b A/a ; B/b self-cross

ww m+ & m

Coat color: Genes A, B, C, D, E, S

A

AY

B

cc C

C

C

D

E e

E e

ee B & b

cc B & b

Agouti, not Yellow (A, not AY)

cc A & a

cc A & a

Genotype ratios: 1:2:1:2:4:2:1:2:1 (“A” here =AY) X X X X Phenotype ratios: 9:3:3:1 Genotype ratios: 1:2:1:2:4:2:1:2:1 AYAY X X X CC:Cc:cc 6:3:3

Hair color genes- - A, B, C, D, E & … S

II. Mention epistasis versus suppression

Genotype -> Phenotype III. Genotype -> Phenotype . . . but with interactions of unknown other genes, environment, + . . .

Lack of Penetrance Variable Expressivity Lack of Penetrance

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