How does crossing-over result in genetic recombination?
A-It mixes half the maternal chromosomes with half the paternal chromosomes.
B- It randomly separates the maternal and paternal chromosomes.
C- It reduces the original cell’s chromosome number by half.
D- It permits the exchange of genetic material between maternal and paternal chromosomes.
The correct answer is D- It permits the exchange of genetic material between maternal and paternal chromosomes.
Crossing-over occurs during meiosis, specifically in prophase I, and it involves the exchange of genetic material between homologous chromosomes. This exchange occurs at the points called chiasmata, where the chromatids of the maternal and paternal chromosomes are joined together.
During crossing-over, sections of DNA are swapped between the maternal and paternal chromosomes, resulting in the genetic recombination of alleles. This genetic recombination leads to the production of new combinations of traits in the offspring, contributing to genetic diversity.
The correct answer is D: crossing-over permits the exchange of genetic material between maternal and paternal chromosomes, which results in genetic recombination.
Crossing-over is a process that occurs during meiosis, specifically during prophase I. During this phase, paired homologous chromosomes align next to each other and form structures called chiasmata. At these chiasmata, genetic material from the maternal chromosome can be exchanged with genetic material from the paternal chromosome.
This exchange of genetic material between the homologous chromosomes creates new combinations of alleles. These new combinations result in genetic recombination, as traits from both parents are mixed and shuffled, leading to greater genetic diversity. Therefore, crossing-over is an important mechanism for creating genetic variation within a species.