# Animal Science Breeding & Genetics

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Animal Science Breeding & Genetics
Original Power Point Created by Casey Osksa Modified by Georgia Agricultural Education Curriculum Office June 2002

Genetics Terms Heterozygous = two different types of genes (Bb)
Homozygous = two similar genes (BB) Dominant Gene = trait overpowers others Recessive Gene = must be accompanied with another recessive gene to express trait Incomplete Dominance = both traits express themselves

Punnet Square Shorthorn Cattle R = Red W = white RW = roan
If a red bull (RR) is mated to a white cow (WW), what color will the calves be?

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Punnet Square If a red bull (RR) is mated to a roan (RW) cow, what color will the calves be?

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Punnet Square P = horned p = polled
If a homozygous horned cow (PP) is mated to a homozygous polled bull (pp), what percent of the calves will be horned, polled?

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Punnet Square If a homozygous horned cow (PP) is mated to a heterozygous horned bull (Pp), what percent of the calves will be polled?

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Punnet Square Mate an Angus bull that is homozygous black and polled (BBPP) to a red shorthorn cow which is homozygous red and horned (bbpp). What is the probability that the offspring will be black? Polled? Horned? Black and Polled?

Punnet Square Black = 100% Polled = 100% Horned = 0%

Punnet Square Now mate two of the offspring which are heterozygous for black/red and polled/horned (BbPp) What is the probability that the offspring will be black? Black Polled? Black Horned? Red? Red Polled? Red Horned?

Punnet Square How do you do a punnet square with multiple genes?
Use all possible gene combinations BbPp = could be BP, Bp, bP,bp 4 x 4 grid

Punnet Square

Punnet Square Black = 12 out of 16 or 75%
Black Polled = 9 out of 16 or 56.25% Black Horned = 3 out of 16 or 18.75% Red = 4 out of 16 or 25% Red Polled = 3 out of 16 or 18.75% Red Horned = 1 out of 16 or 6.25%

Punnet Square Mate a heterozygous bull (BbPp) to a homozygous cow (BBPP) What are the outcomes?

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Punnet Square Mate a (BbPp) bull to a (BBPp) cow
what are the outcomes?

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