Download Genetics Problems A

Biology Genetics Problems
Ch 8
"Genetics and Probability"
1) What is the probability of the third child in a family of three children being a boy?
2) What is the probability of that family having three boys?
3) What is the probability of a family having two girls, and then a boy?
4) What is the probability of a family having two girls and one boy?
5) Draw a Punnett square to show the offspring possible between a man heterozygous for tongue
rolling and a woman who cannot roll her tongue?
a) What is the genotypic ratio in this cross:
b) What is the phenotypic ratio in this cross?
6) A genetic cross, like the one above, involving only one pair of alleles that determines one trait is
called a
cross.
(It only involves one gene!)
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7) What would be the genotype of a woman homozygous dominant for tongue rolling and
homozygous dominant for earlobes?
8) What alleles would be found in the woman’s gametes?
9) What would be the genotype of a man heterozygous for both tongue rolling and ear lobes?
10) What alleles would be found in the man’s gametes?
11) Using a Punnett square, determine the genotype and phenotype of all the children?
Genotypes:
Ratio:
Phenotypes:
Ratio:
12) What is the genotype of a person heterozygous for both tongue rolling and ear lobes?
13) What are all of the possible gamete combinations made by the person above?
14) What is the expected phenotypic ratio of the offspring between a cross of two people heterozygous
for tongue-rolling and earlobes?
15) A genetic cross involving two pairs of alleles that determine two separate traits is called a
cross.
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