Transcript How to Set up a Dihybrid Cross

Bellwork: Mon. Jan. 11 , 2016
Short hair is dominant: SS… Ss
long hair is recessive: ss
1. Show a cross between two heterozygous guinea pigs. What % of the
offspring will have short hair? ________
What %of the offspring will have long hair? _______
2. Two short haired guinea pigs are mated several times. Out of 100
offspring, 25 of them have long hair. What are the probable
genotypes of the parents? ________ x ___________
How to Set up a Dihybrid Cross
And Punnett square
Traits:
Curly Hair (A)
Straight Hair (a)
Brown Hair (B)
Blonde Hair (b)
Curly Hair (A)
Straight Hair (a)
How to Set up a Dihybrid Cross
Do this:
Genotypic Ratio:
Phenotypic Ratio
AaBb X
AAbb
Brown Hair (B)
Blonde Hair (b)
Curly Hair (C)
Straight Hair (c)
Cross a female with homozygouscurly, heterozygous Brown Hair (B)
brown hair to a male with, straight blonde hair: 1st, Blonde Hair (b)
Hair Color, Texture Cross
write the cross:
________ x ________
Genotypic Ratio:
Phenotypic ratio:
Bellwork: Tues. Jan. 12, 2016
1.
White coat color (WW) is co-dominant to red
coat color in cattle (RR). What should the
genotypes and phenotypes be for parental cattle
if a farmer wants only cattle with roan coats.
Cross:____________________
Genotype(s):
Phenotype(s)
2. A florist has flowers that exhibit
incomplete dominance. Red petals are incompletely
dominant to white petals. What would the
genotype(s) and phenotype(s) be for offspring of
a red flower and a white flower?
Cross:____________________
Genotype(s):
Phenotype(s):