Ask Question, Ask an Expert

+1-415-315-9853

info@mywordsolution.com

Ask Biology Expert

"Consider a pair of homologous chromosomes heterozygous for three genes (e.g., ABC/abc) during prophase I of meiosis. Let the sister chromatids of one homolog be numbered 1 and 2 (ABC); and the sister chromatids of the other homolog be numbered 3 and 4 (abc).

"Assume a double crossover occurs in this pair of chromosomes that results in chromatids of the genotype Abc, ABC, aBc and abC. If the first crossover (the one between A and B) involves chromatids 1 & 4, which chromatids could be involved in the second crossover?"

A. 1 & 2
B. 1 & 3
C. 1 & 4
D. 1 & 3 or 1 & 4 or 2 & 3 or 2 & 4
E. any two of the four chromatids

I'm a little confused about how to set up this problem. When the problem says "sister chromatids...1 and 2 (ABC)" and "sister chromatids...3 and 4 (abc)" does that mean that ABC are on both chromatids 1 and 2, and abc are on both chromatids 3 and 4? I.e.,

1 A----B----C
2 A----B----C
3 a----b----c
4 a----c----c

If not, I'm not sure which alleles are on which chromatids.

Also, I initially thought that answers A and E could not be correct because I thought that only nonsister chromatids could cross over. But if that's true, how does a double crossover between 1 and 3 or 1 and 4 produce the genotype ABC? Couldn't that only be obtained with a double crossover between 1 and 2? Or does a crossover + and reverse crossover count as a double crossover? I.e.,

1 A---B---C
3 a---b---c

crosses once between A and B to produce A---b---c, and once more between A and B to produce A---B---C?

As you can see, I'm a little confused. Can you please describe how to do this problem, and include the answer so that I can make sure I understand your explanation when I try to problem on my own?

Biology, Academics

  • Category:- Biology
  • Reference No.:- M928183

Have any Question? 


Related Questions in Biology

Track the ingestion and digestion of a ham and cheese

Track the ingestion and digestion of a ham and cheese sandwich on whole wheat bread with lettuce, green pepper, and tomatoes. Describe the fate of this sandwich from the time you eat it. Be very detailed as to the digest ...

Given what you know about how natural selection works

Given what you know about how Natural Selection works, explain why Sickle cell disease hasn't been eradicated from the population.

The branch of agriculture which deals with the feeding

The branch of agriculture which deals with the feeding, shelter, health and breeding of the domestic animals is called?

How might 32p and 35s be used to demonstrate that the

How might 32P and 35S be used to demonstrate that the transforming principle is DNA? Briefly outline an experiment that would show that DNA rather than protein is the transforming principle.

What are the characteristics of tropical waters temperate

What are the characteristics of tropical waters, temperate waters and polar waters?

If someone has calf pain which muscle would be in pain and

If someone has calf pain. Which muscle would be in pain and would the pain be a cause of a tear to the origin or insertion?

Assignment professional standards and institutional

Assignment: Professional Standards and Institutional Ethics In each case, answer the questions at the end of the case and give researched references to support your assertions; also, explain what would be the ethical cou ...

Which phylloclade commonly found in xerophytic plants that

Which phylloclade commonly found in xerophytic plants that is modified?

1 the ductus arteriosus and the ductus venosus are two key

1) The ductus arteriosus and the ductus venosus are two key vessels in the fetal circulation that are absent in the adult circulation. What are their function in the fetus? Why are they necessary? 2) At birth, the fetal ...

Explain how resource partitioning led to character

Explain how resource partitioning led to character displacement in the interactions between the benthic and limnetic sticklebacks in Paxton Lake.

  • 4,153,160 Questions Asked
  • 13,132 Experts
  • 2,558,936 Questions Answered

Ask Experts for help!!

Looking for Assignment Help?

Start excelling in your Courses, Get help with Assignment

Write us your full requirement for evaluation and you will receive response within 20 minutes turnaround time.

Ask Now Help with Problems, Get a Best Answer

WalMart Identification of theory and critical discussion

Drawing on the prescribed text and/or relevant academic literature, produce a paper which discusses the nature of group

Section onea in an atwood machine suppose two objects of

SECTION ONE (a) In an Atwood Machine, suppose two objects of unequal mass are hung vertically over a frictionless

Part 1you work in hr for a company that operates a factory

Part 1: You work in HR for a company that operates a factory manufacturing fiberglass. There are several hundred empl

Details on advanced accounting paperthis paper is intended

DETAILS ON ADVANCED ACCOUNTING PAPER This paper is intended for students to apply the theoretical knowledge around ac

Create a provider database and related reports and queries

Create a provider database and related reports and queries to capture contact information for potential PC component pro