Ch 3 HW Genetic

Albinism, lack of pigmentation in humans, results from an autosomal recessive gene (a). Two parents with normal pigmentation have an albino child. What is the probability that their next three children will be albino?

1/64

Albinism, lack of pigmentation in humans, results from an autosomal recessive gene (a). Two parents with normal pigmentation have an albino child. What is the probability that their next child will be an albino girl?

1/8

If Patricia and Les have another child, what is the probability that they will have a daughter that is affected with

1/8

What is the probability that Mary and Justin will have an affected child?

1/8

If this is an autosomal recessive disorder, what is the probability that individual II-3 is a heterozygous carrier of the disorder? Express your answer as a fraction (example: 3/5).

2/3

Two organisms, AABBCCDDEE and aabbccddee, are mated to produce an F1 that is self-fertilized. If the capital letters represent dominant, independently assorting alleles. How many different genotypes will occur in the F2?

243

The phenotype of vestigial (short) wings (vg) in Drosophila melanogaster is caused by a recessive mutant gene that independently assorts with a recessive gene for hairy (h) body. Assume that a cross is made between a fly with normal wings and a hairy body and a fly with vestigial wings and normal body hair. The wild-type F1 flies were crossed among each other to produce 1024 offspring. Which phenotypes would you expect among the 1024 offspring, and how many of each phenotype would you expect?

Phenotypes: wild, vestigial, hairy, and vestigial hairy; Numbers expected: wild (576), vestigial (192), hairy (192), and vestigial hairy (64).

What conditions are likely to apply if the progeny from the cross AaBb × AaBb appear in the 9:3:3:1 ratio?

complete dominance, independent assortment, and no gene interaction

In a Chi-square test, as the value of the χ2 increases, the likelihood of rejecting the null hypothesis ________.

increases

The Chi-square test involves a statistical comparison between measured (observed) and predicted (expected) values. One generally determines degrees of freedom as ________.

one less than the number of classes being compared

Chi-square analysis can help us to decide whether __________.

our observations of an event differ from our expectations

In a Chi-square analysis, what general condition causes one to reject (fail to accept) the null hypothesis?

usually when the probability value is less than 0.05

Mendel crossed two pea plants with round seeds. All seeds of the offspring were round. He then crossed a plant with round seeds to a plant with wrinkled seeds and all offspring had wrinkled seeds. Which of the following is true?

wrinkled is dominant

Assuming independent assortment, what proportion of the offspring of the cross AaBbCcDd × AabbCCdd will have the aabbccdd genotype?

0

Albinism, lack of pigmentation in humans, results from an autosomal recessive gene. Two parents with normal pigmentation have an albino child. What is the probability that their next child will be wild type?

0%

Polydactyly is expressed when an individual has extra fingers and/or toes. Assume that a man with six fingers on each hand and six toes on each foot marries a woman with a normal number of digits. Having extra digits is caused by a dominant allele. The couple has a son with normal hands and feet, but the couple's second child has extra digits. What is the probability that their next child will have polydactyly?

1/2

The autosomal (not X-linked) gene for brachydactyly, short fingers, is dominant to normal finger length. Assume that a female with brachydactyly in the heterozygous condition is married to a man with normal fingers. What is the probability that their first child will have brachydactyly?

1/2

Tightly curled or wooly hair is caused by a dominant gene in humans. If a heterozygous curly-haired person marries a person with straight hair, what percentage of their offspring would be expected to have straight hair?

50% straight

How many kinds of gametes will be expected from an individual with the genotype PpCcTTRr?

8

Which of the following best describes the relationship at the molecular level between mutant alleles and phenotype?

A mutant allele can have different effects depending on the gene product's function.

If an F2 generation from a self-cross always yields offspring in a 3:1 phenotypic ratio, which of the following P crosses could have occurred?

AA × aa

Under what conditions does one expect a 1:1:1:1 ratio?

AaBb × aabb This occurs in a cross involving doubly heterozygous individuals crossed to fully recessive individuals. The genes involved assort independently of each other.

Select all that apply.

DdWw x DdWw

In what ways is sample size related to statistical testing?

By increasing sample size, one increases the reliability of the statistical test and decreases the likelihood of erroneous conclusions from chance fluctuations in the data.

Select all that apply.

DdWw x Ddww

Select all apply

DdWw x ddww

Considering the Mendelian traits tall (D) versus dwarf (d) and violet (W) versus white (w), consider the crosses below and determine the genotypes of the parental plants by analyzing the phenotypes of the offspring.

DDWw x Ddww DdWw x DDww DDWw x DDww

What is independent assortment?

During gamete formation, segregating pairs of unit factors assort independently of each other

If this is an autosomal recessive disorder, of the following individuals, which is NOT an obligate carrier?

III-6

Which of the following statements is true regarding individual III-5? Select all that apply.

Individual III-5 is male Individual III-5 is affected by the genetic condition Individual III-5 is the proband.

A certain type of congenital deafness in humans is caused by a rare autosomal recessive gene. In a mating involving a deaf man and a deaf woman, could some of the children have normal hearing?

No, since the gene in question is recessive, both of the parents are homozygous and one would not expect normal hearing in the offspring

How did Mendel's work support the chromosomal theory of inheritance?

The behavior of chromosomes during meiosis, as observed under a microscope, correlated with Mendel's principles of inheritance.

Which of the following describes the product law?

The probability of two or more independent events occurring simultaneously is equal to the product of their individual probabilities.

Assume that a black guinea pig crossed with an albino guinea pig produced 5 black offspring. When the albino was crossed with a second black guinea pig, 4 black and 3 albino offspring were produced. What genetic explanation would apply to these data?

albino = recessive; black = dominant

Mendel indicated that traits were made up of unit factors. Today, we call unit factors ________.

alleles

Assuming no crossing over between the gene in question and the centromere, when do alleles segregate during meiosis?

anaphase I

Which of the following is a possible mechanism of inheritance for the disorder presented in the pedigree? Select all that apply.

autosomal recessive and X-linked recessive.