Low platelet count it a recessively inherited trait. Reevaluation of the genetic screen indicates that Nikoleta is homozygous dominant normal for a trait that causes low platelet count and her husband is homozygous recessive If the F, offspring has normal platelets and beta-thalassemia. What are the parental gametes? Based on the F_1 progeny phenotype given and the parental gametes, write the two possible genotypes. What is the gamete frequency it the two genotypes in (b) were crossed with each other? What is the phenotype frequency for the cross in (c)? Use the evidence from the case to advice Nikoleta and her husband about having a family. Nikoleta and her husband Andrew conceived four times. What are the possible combinations for a boy and get for each time Mrs. Stamos became pregnant? Solution Legends- XX-female XY-male HH/hh-homozygous trait for platelets count Hh-heterozygous trait for platelets count 1.a. The parental gametes will be – XHXH - homozygous dominant mother XhY- homozygous recessive b. possible genotype are- 2XHXh and 2XHY c. gamete frequency for XHXh will be 2/4=1/2 gamete frequency for XHY will be 2/4=1/2 d. phenotype frequency is as follows Parents Homozygous dominant mother Homozygous recessive father XHXH XhY Gametes XH XH Xh Y Male/female XH XH Xh XHXh heterozygous dominant XHXh heterozygous dominant Y XHY heterozygous dominant XHY heterozygous dominant F1 progeny 2. From the f1 progeny it is clear that all offspring are heterozygous, as platelets count is homozygous recessive trait. All children will be normal. Male/female XH XH Xh XHXh heterozygous dominant XHXh heterozygous dominant Y XHY heterozygous dominant XHY heterozygous dominant.

1. Low platelet count it a recessively inherited trait. Reevaluation of the genetic screen indicates
that Nikoleta is homozygous dominant normal for a trait that causes low platelet count and her
husband is homozygous recessive If the F, offspring has normal platelets and beta-thalassemia.
What are the parental gametes? Based on the F_1 progeny phenotype given and the parental
gametes, write the two possible genotypes. What is the gamete frequency it the two genotypes in
(b) were crossed with each other? What is the phenotype frequency for the cross in (c)? Use the
evidence from the case to advice Nikoleta and her husband about having a family. Nikoleta and
her husband Andrew conceived four times. What are the possible combinations for a boy and get
for each time Mrs. Stamos became pregnant?
Solution
Legends-
XX-female
XY-male
HH/hh-homozygous trait for platelets count
Hh-heterozygous trait for platelets count
1.a. The parental gametes will be –
XHXH - homozygous dominant mother
XhY- homozygous recessive
b. possible genotype are- 2XHXh and 2XHY
c. gamete frequency for XHXh will be 2/4=1/2
gamete frequency for XHY will be 2/4=1/2
d. phenotype frequency is as follows
Parents Homozygous dominant mother Homozygous recessive father
XHXH XhY
Gametes XH XH
Xh Y
Male/female
XH
XH
Xh
XHXh
heterozygous dominant
XHXh

2. heterozygous dominant
Y
XHY
heterozygous dominant
XHY
heterozygous dominant
F1 progeny
2. From the f1 progeny it is clear that all offspring are heterozygous, as platelets count is
homozygous recessive trait. All children will be normal.
Male/female
XH
XH
Xh
XHXh
heterozygous dominant
XHXh
heterozygous dominant
Y
XHY
heterozygous dominant
XHY
heterozygous dominant