Biology 211: Genetics Problem Set 2

For each of the following genotypes, give all of the possible gametes.

Guinea Pigs:

Rough coat = R
Smooth coat = r

Pea Plant:

Tall = T
Dwarf = t

Pea Plant:

Tall = T
Dwarf = t
Yellow = Y
Green = y

Color Vision Sex-Linked:

Dominant for Color Vision = X^C
Recessive for Color Vision = X^©

Human Hair Line:

Widow's Peak = W
No Widow's Peak = w

Sickle Cell Anemia Incomplete Dominance:

Normal = SS
Sickle Cell Disease = ss
Sickle Cell Trait = Ss

Hemophilia Sex-Linked:

Normal = X^H
Hemophilia = X^h

Pea Plants Incomplete Dominance:

Red = RR
White = rr
Pink = Rr

What would be the genotype and phenotype of a cross between a red flower and a white flower that exhibit incomplete dominance?

WW
WWSS
Tt
Ttgg
AaBb

WW : W
homozygous dominant parent: since both alleles of the parent are W, all gametes will have the W allele
WWSS : WS
parent homozygous dominant for both traits: since only W & S alleles are present, only WS gametes will be produced
Tt : T, t
heterozygous parent: since T & t alleles are present in the parent, both T & t gametes can be produced
Ttgg : Tg, tg
parent heterozygous for T, homozygous recessive for G: both T & t alleles are present for the T trait, but only the g allele is present for the G trait, so half of the gametes will have a T & g, & the other half will have a t & g
AaBb : AB, Ab, aB, ab
parent heterozygous for both traits: both A & a alleles are present for the A trait, and both B & b alleles are present for the G trait, so there are 4 possible gametes possible by matching each A allele with each B allele

: Cross Parents RR x Rr

: Punnett Square:

: Phenotype:

: Genotype:

: Cross Parents RR x Rr

: Punnett Square:

: Phenotype: 100% rough coat

: Genotype: 50% RR, 50% Rr (1:1 for RR:Rr)

: Cross Parents TT x tt

: Punnett Square:

: Phenotype:

: Genotype:

: Cross Parents TT x tt

: Punnett Square:

: Phenotype: 100% tall

: Genotype: 100% Tt

: Cross Parents TtYy x TtYy

: Punnett Square:

: Phenotype:

: Cross Parents TtYy x TtYy

: Punnett Square:

: Phenotype: 9:3:3:1 for tall,yellow:tall,green:dwarf,yellow:dwarf,green

: Cross Parents X^CX^© x X^CY

: Punnett Square:

: Phenotype:

Cross Parents X^CX^© x X^CY
Punnett Square:

Phenotype:	75% normal vision, 25% colorblind (3:1 for normal vision:colorblind) 0% of the female offspring will be colorblind (half will be carriers); 50% of the male offspring will be colorblind

: Cross Parents Ww x Ww

: Punnett Square:

: Phenotype:

: Cross Parents Ww x Ww

: Punnett Square:

: Phenotype: 75% widow's peak, 25% no widow's peak (3:1 for widow's peak:no widow's peak)

: Cross Parents Ss x Ss

: Punnett Square:

: Phenotype:

: Cross Parents Ss x Ss

: Punnett Square:

: Phenotype: 25% normal, 50% sickle cell trait, 25% sickle cell disease (1:2:1 for normal:sickle cell trait:sickle cell disease)

: Cross Parents X^HX^h x X^HY

: Punnett Square:

: Phenotype:

: Genotype:

Cross Parents X^HX^h x X^HY
Punnett Square:

Phenotype:	75% normal, 25% hemophilic (3:1 for normal:hemophilic) 0% of the female offspring will be hemophilic (half will be carriers); 50% of the male offspring will be hemophilic
Genotype: 25% X^HX^H, 25% X^HX^h, 25% X^HY, 25% X^hY

: Cross Parents Rr x Rr

: Punnett Square:

: Phenotype:

: Genotype:

: Cross Parents Rr x Rr

: Punnett Square:

: Phenotype: 25% red, 50% pink, 25% white (1:2:1 for red:pink:white)

: Genotype: 25% RR, 50% Rr, 25% rr

: Phenotype: 100% pink

: Genotype: 100% Rr