Genetics Answers

Which of the following statements about variation is true? Select all that apply.

Variation comes from a combination of traits from the organism's mother and father.

Variation is caused by the presence of alleles.

Variation only affects physical features such as hair color, eye color, and height.

Variation is any difference between individual cells or organisms caused by mutation.

Sometimes, two alleles are neither dominant nor recessive, therefore, both alleles are expressed separately in a heterozygous individual. This is called codominance. Which of the following is an example of codominance?

In guinea pigs, black hair is dominant over white hair. A homozygous black guinea pig is crossed with a homozygous white guinea pig. The first generation of offspring are black.

If you cross a plant with blue flowers with a plant with yellow flowers, the offspring will have blue flowers with yellow spots.

If you cross a rhododendron plant with red flowers with a rhododendron plant with white flowers, the offspring will have pink flowers.

A white female cat mates with a brown male cat. The resulting offspring are orange.

Background:

In certain types of cattle, three colors exist:

• white (WW), white hairs
• red hair (RR), red hairs
• roan (RW), a mixture of red and white hairs

Roan is a codominant condition.

Question:

A breeder wants to only produce roan-colored cattle. Which of the following parents should she select to only produce roan-colored offspring? Select all that apply.

black-haired parent

white-haired parent

roan-haired parent

red-haired parent

What is the phenotypic ratio of the offspring when a man who has type A blood, and whose mother had type O blood, marries a woman who has type AB blood?

 2 type A : 1 type AB : 1 type B

3 type A: 1 type B

1 type A : 1 type O

1AA :1AB : 1AO : 1BO

Which of the following situations is the result of epistasis?

A mouse has black fur, black eyes, and black skin.

A mouse has white fur, pink eyes, and pink skin.

A mouse has white fur with black spots and black eyes.

A mouse has black fur with white spots and black eyes.

Two mice with gray fur are crossed. They produce 15 gray, 8 black, and 6 white offspring. In one paragraph, using your own words, explain the inheritance of these colors in the mice. What phenotypes would you expect in the offspring of a cross between a gray mouse and a white mouse? Be sure to include proper spelling, grammar, and punctuation.

 If a man carries a recessive sex-linked trait on his X chromosome, what is the possibility that his children will inherit the disease if their mother is not a carrier of the disease?

0%

100%

75%

50%

In guinea pigs, black hair is dominant over white hair. If a homozygous black guinea pig (father) were crossed with a homozygous white guinea pig (mother), the first generation of offspring would be all black.

Match the mother's and father's genotypes and phenotypes to their correct description.

1.mother's phenotype

2.father's phenotype

3.father's genotype

4.mother's genotype

a.black

b.HH

c.white

d.hh

A condition in which both alleles of a heterozygous condition are expressed as a blending of traits is ______.

incomplete dominance

sex-linked

transformation

crossing over

 During which phase of meiosis does variation occur?

anaphase I

cytokinesis

interphase

telophase I