Multiple Choice
After homologous chromosomes pair up during prophase I of meiosis, which event typically occurs next?
3
views
4. Genetic Mapping and Linkage
Crossing Over and Recombinants
Struggling with Genetics?
Join thousands of students who trust us to help them ace their exams!Watch the first videoMultiple Choice
Why does cleaving at points a and b in Figure 2 result in non-recombinant chromosomes during crossing over?
A
Because the cleavages only affect the telomeres, which do not contain genes involved in recombination.
B
Because the cleavages occur at identical positions on homologous chromatids, leading to exchange of identical genetic material.
C
Because the cleavages disrupt the centromere, resulting in chromosome loss rather than recombination.
D
Because the cleavages occur on non-homologous chromosomes, preventing any genetic exchange.
Verified step by step guidance1
Understand that crossing over involves the exchange of genetic material between homologous chromosomes at corresponding positions called loci.
Recognize that cleaving at points a and b means breaks occur at the same positions on both homologous chromatids.
Since the breaks are at identical positions, the segments exchanged between chromatids are genetically identical, so no new combinations of alleles are formed.
This results in chromosomes that retain their original combination of alleles, which are called non-recombinant chromosomes.
Therefore, the key reason is that the exchange involves identical genetic material at the same loci, preventing the creation of recombinant chromosomes.
Related Videos
Related Practice
Crossing Over and Recombinants practice set
Problem sets built by lead tutorsExpert video explanations