/*! This file is auto-generated */ .wp-block-button__link{color:#fff;background-color:#32373c;border-radius:9999px;box-shadow:none;text-decoration:none;padding:calc(.667em + 2px) calc(1.333em + 2px);font-size:1.125em}.wp-block-file__button{background:#32373c;color:#fff;text-decoration:none} Problem 4 Why does more crossing over occu... [FREE SOLUTION] | 91影视

91影视

Log out

Learning Materials

Features

Discover

Chapter 5: Problem 4

Why does more crossing over occur between two distantly linked genes than between two genes that are very close together on the same chromosome?

Short Answer

Expert verified
Answer: More crossing over occurs between two distantly linked genes than between two closely linked genes on the same chromosome because the formation of chiasmata is more likely between distant genes. The increased likelihood of chiasmata formation between distant genes results in a higher frequency of crossing-over events and genetic recombination, ultimately contributing to greater genetic diversity in the offspring.

Step by step solution

01

Understanding Crossing Over

Crossing over is a process that occurs during meiosis, where homologous chromosomes exchange genetic material. This process increases genetic diversity within the offspring, as it creates new combinations of alleles in the resulting gametes. Crossing over occurs during the prophase I stage of meiosis, where homologous chromosomes pair up and form structures known as chiasmata.
02

Proximity and Crossing Over

The probability of crossing over between two genes is influenced by their physical distance on a chromosome. If two genes are very close or nearby, it is less likely that crossing over will occur between them. This is because the chiasmata, which are the points of exchange, are less likely to form between two closely linked genes. As a result, their alleles will tend to be inherited together, also referred to as genetic linkage.
03

Greater Distance and Increased Frequency of Crossing Over

Conversely, when two genes are further apart on the chromosome, there is a greater likelihood that one or more chiasmata will form between them during prophase I of meiosis. This increases the chance of genetic recombination and crossing over between the two genes, resulting in a greater diversity of alleles in the offspring. The frequency of crossing-over events between two genes is proportional to the distance separating them.
04

Conclusion

In summary, more crossing over occurs between two distantly linked genes than between two closely linked genes on the same chromosome because of the increased likelihood of chiasmata formation between distant genes. This increased probability of chiasmata formation results in a higher frequency of crossing-over events and genetic recombination, ultimately contributing to greater genetic diversity in the offspring.

Unlock Step-by-Step Solutions & Ace Your Exams!

  • Full Textbook Solutions

    Get detailed explanations and key concepts

  • Unlimited Al creation

    Al flashcards, explanations, exams and more...

  • Ads-free access

    To over 500 millions flashcards

  • Money-back guarantee

    We refund you if you fail your exam.

Over 30 million students worldwide already upgrade their learning with 91影视!

One App. One Place for Learning.

All the tools & learning materials you need for study success - in one app.

Get started for free

Most popular questions from this chapter

Three loci, mitochondrial malate dehydrogenase that forms \(a\) and \(b(M D H a, M D H b),\) glucouronidase that forms 1 and 2 \((G U S 1, G U S 2),\) and a histone gene that forms \(+\) and \(-\left(H^{+},\right.\) \(\left.H^{-}\right),\) are located on chromosome \(\\# 7\) in humans. Assume that the \(M D H\) locus is at position \(35, G U S\) at position \(45,\) and \(H\) at position \(75 .\) A female whose mother was homozygous for \(M D H a, G U S 2,\) and \(H^{+}\) and whose father was homozygous for \(M D H b, G U S 1,\) and \(H^{-}\) produces a sample of 1000 egg cells. Give the genotypes and expected numbers of the various types of cells she would produce. Assume no chromosomal interference.

Assume that investigators crossed a strain of flies carrying the dominant eye mutation Lobe on the second chromosome with a strain homozygous for the second chromosome recessive mutations smooth abdomen and straw body. The \(\mathrm{F}_{1}\) Lobe females were then backcrossed with homozygous smooth abdomen, straw body males, and the following phenotypes were observed: (a) Give the gene order and map units between these three loci. (b) What is the coefficient of coincidence?

List some of the differences between a linkage map obtained by analyzing crossovers and a physical map obtained by sequencing the DNA.

An organism of the genotype \(A a B b C c\) was testcrossed to a triply recessive organism (aabbcc). The genotypes of the progeny are presented in the following table. (a) If these three genes were all assorting independently, how many genotypic and phenotypic classes would result in the offspring, and in what proportion, assuming simple dominance and recessiveness in each gene pair? (b) Answer part (a) again, assuming the three genes are so tightly linked on a single chromosome that no crossover gametes were recovered in the sample of offspring. (c) What can you conclude from the actual data about the location of the three genes in relation to one another?

A female of genotype \\[ \frac{a}{+}+b^{c} \\] produces 100 meiotic tetrads. Of these, 68 show no crossover events. Of the remaining 32,20 show a crossover between \(a\) and \(b, 10\) show a crossover between \(b\) and \(c,\) and 2 show a double crossover between \(a\) and \(b\) and between \(b\) and \(c .\) Of the 400 gametes produced, how many of each of the 8 different genotypes will be produced? Assuming the order \(a-b-c\) and the allele arrangement previously shown, what is the map distance between these loci?
See all solutions

Recommended explanations on Biology Textbooks

Biological Structures

Read Explanation

Plant Biology

Read Explanation

Cell Cycle

Read Explanation

Biology Experiments

Read Explanation

Cellular Energetics

Read Explanation

Organ Systems

Read Explanation
View all explanations

What do you think about this solution?

We value your feedback to improve our textbook solutions.

Study anywhere. Anytime. Across all devices.