BIO 202 Chapter 15: Chapter 15 Learning Objectives

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plumgoldfish775

15 Jan 2019

School

Stony Brook University

Department

Biology

Course

BIO 202

Professor

Susan Erster

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Document Summary

Chromosome theory of inheritance chromosomes carry hereditary material; the behavior of chromosomes during gamete formation and fertilization is the physical mechanism that"s responsible for inheritance. During early embryonic development in humans, there is a mass of tissue that is an unspecified gonad. Sry gene is a protein that functions as a transcription factor, meaning that it turns on transcription or reading of dna to rna of this gene. Pedigree charts that allow us to track the passage of a particular trait through generations. Disorders: cystic fibrosis inherited as an autosomal recessive gene. If the gene that leads to cystic fibrosis is mutated, it enables a protein called cftr, phenotypes that result from this are issues with the lungs. Cystic fibrosis causes the loss of the cl- transporter, cl- can"t leave the cells, the water doesn"t follow, and the mucus becomes too dehydrated.

Related Questions

Calvin Bridgesâs classic study of nondisjunction of sex chromosomes provided support for the chromosome theory of inheritance. Bridges performed crosses with fruit flies, tracking the sex-linked eye-color trait. Red-eyed males were crossed with white-eyed females. Which of the following is an accurate explanation of his findings?

a. The offspring were mostly white-eyed females and red-eyed males, but 1/ 2,000 offspring were white-eyed females (genotype XX) or red-eyed males (genotype XY).

b. The offspring were mostly white-eyed males and red-eyed females, but 1/ 2,000 offspring were white-eyed females (genotype XXY) or red-eyed males (genotype XO).

c. The offspring were mostly white-eyed females and red-eyed males, but 1/ 2,000 offspring were white-eyed females (genotype XXY) or red-eyed males (genotype XO).

d. The offspring were mostly white-eyed males and red-eyed females, but 1/ 2,000 offspring were white-eyed females (genotype XX) or red-eyed males (genotype XO).

e. The offspring were mostly white-eyed males and red-eyed females, but 1/ 2,000 offspring were white-eyed females (genotype XXX) or red-eyed males (genotype XY).

browngoat107

The following question is a sex-linked trait. Review the patterns of inheritance of sex-linked traits before answering the following questions. Make sure to indicate chromosomes and alleles in your answers when necessary.

Hemophilia is a caused by a recessive mutation found on the X chromosome in humans. The recessive allele (X^h) is associated with abnormal blood clotting (hemophilia), while the dominant allele (X^N) causes normal blood clotting.

A man with normal blood clotting and woman who is heterozygous are going to have a child. What is the probability of an offspring who is a carrier of hemophilia, and if so, the sex(es) of the offspring?

A. Chances are 25% of a son who is a carrier

B. There is no chance of an offspring who is a carrier

C. Chances are 50% of either a son or a daughter who is a carrier

D. All offspring, male or female, will be carriers

E. Chances are 1 in 4 of a daughter who is a carrier

2. Two fruit flies, one with red eyes and one with white eyes mate and have an offspring with white eyes. Having red eyes is a dominant trait (R) while white eyes (w) is recessive. Based on this information, what must be the genotypes of the parental white-eyed fruit fly and the parental red-eyed fruit fly?

A. Red-Eyed fruit fly: Rw

White-eyed fruit fly: ww

B. Red-Eyed fruit fly: RR

White-eyed fruit fly: wR

C. Red-Eyed fruit fly: R

White-eyed fruit fly: w

D. Red-Eyed fruit fly: rr

White-eyed fruit fly: wr

E. Red-Eyed fruit fly: RR

White-eyed fruit fly: ww

1. The eye color of wild-type Drosophila flies is red. Differentmutations in a single or in multiple genes lead to flies with whiteeyes. Mutations in the w gene on the X chromosome lead to whiteeyes instead of the normal red. You have isolated both a white-eyedmutation (designated W-1) that gives a dominant phenotype, and awhite-eyed mutation (designated w-2) that gives a recessivephenotype.

(a) A white-eyed male from the W-1 line is crossed to awild-type female. What color eyes will the female progeny from thiscross have?

(b) What color eyes will the male progeny from the cross in part(a) have?

(c) One of the female progeny from the cross in part (a) ismated to a white-eyed male from the w- 2 line. What fraction of thewhite-eyed progeny from this cross will be female?

2. The body color of Drosophila adult flies is regulated bymultiple genes, including the autosomal ebony gene. Ebony body (e)is recessive to the wild type (yellowish) body (e+). A second gene,which is X-linked, controls bristle shape. Normal bristle shape(f+) is dominant to the mutant forked bristles (f). A female withforked bristles that is heterozygous for the body color gene ismated with an ebony body male (his bristles are normal).

(a) What are the genotypes of the parents?

(b) Using a Punnett square, determine the expected proportionsof each possible progeny phenotype. Since there is a sex-linkedgene here, be sure to include consider sex as part of thephenotype.

3. Describe in your own words what a balancer chromosome is andwhy it is important in fly genetics (you will have to do someresearch for this one!)

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BIO 202 Chapter 15: Chapter 15 Learning Objectives

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