Genetics ...Patterns of Inheretence

c

A color-blind woman marries a man who is not color-blind. All of their sons, but none of their daughters, are color-blind. Which of the following statements correctly explains these results? a) the gene for color vision is incompletely dominant to the gene for sex determination b) the gene for color vision is completely dominant to the gene for sex determination c) the gene for color vision is codominant with the gene for sex determination d) the gene for color vision is linked to the X chromosome e) the gene for color vision is linked to the Y chromosome

c

A monohybrid cross is a) the second generation of a self-fertilized plant. b) a breeding experiment in which the parental varieties have only one trait in common. c) a breeding experiment in which the parental varieties differ in only one character. d) a triploid plant that results from breeding two very different plants. e) a breeding experiment in which the parental varieties have only one prominent trait.

codominance and pleiotropy

A sickle-cell disease is an example of

0 black-eyed: 1 orange-eyed

All the offspring of a cross between a black-eyed mendelien and an orange-eyed mendelien have black eyes. What is the expected phenotypic ratio of a cross between two orange-eyed mendeliens?

incompletely dominant

All the offspring of a cross between a red-flowered plant and a white-flowered plant have pink flowers. This means that the allele for red flowers is __________ to the allele for white flowers.

sex-linked gene

Any gene located on a sex chromosome is called a

linked; do not sort independently during meiosis

Genes located close together on the same chromosomes are referred to as _______ genes and generally __________.

d

Imagine that we mate two black Labrador dogs with normal vision and find that three of the puppies are like the parents, but one puppy is chocolate with normal vision and another is black with PRA (disease of vision). We can conclude that a) both of the parents are homozygous for both traits b) one of the parents is homozygous for both traits c) the same alleles that control coat color can also cause PRA d) the alleles for color and vision segregate independently during gamete formation e) the alleles for color and vision segregate dependelty during gamete formation

do not follow the laws of independent assortment

Linked genes generally

the male's phenotype results entirely from his single X-linked gene

Recessive X-linked traits are more likely to be expressed in a male fruit fly than a female fruit fly because

men need to inherit only one copy of the recessive allele for the condition to be fully expressed

Sex-linked conditions are more common in men than in women because

9:3:3:1

The phenotypic ratio resulting from a dihybrid cross showing independent assortment is expected to be

true-breeding

Varieties of plants in which self-fertilization produces offspring that are identical to the parents are referred to as

d

Which of the following statements regarding cross-breeding and hybridization is false? a) The offspring of two different varieties are called hybrids. b) Hybridization is also called a cross. c) The parental plants of a cross are the P generation. d) The hybrid offspring of a cross are the P1 generation. e) The hybrid offspring of an F1 cross are the F2 generation.

testcross

a mating between an individual of unknown genotype and an individual homozygous recessive for the trait of interest

polygenic inheritance

a situation where a single phenotypic character is determined by the additive effects of two or more genes

locus

the location of a gene on a chromosome