Question

The crossing over that results in genetic recombination in higher organisms occurs between

• A. Non-sister chromatids of a bivalent
• B. Two daughter nuclei
• C. Two different bivalents
• D. Sister chromatids of a bivalents

Answer 1

The correct option is A Non-sister chromatids of a bivalent

The chromosomal crossover is the exchange of genetic material between homologous chromosomes that results in recombinant chromosomes. It is one of the final phases of genetic recombination, which occurs during prophase I of meiosis during a process called synapsis. Synapsis begins before the synaptonemal complex develops, and is not completed until near the end of prophase I. Crossover usually occurs when matching regions on matching chromosomes break and then reconnect to the other chromosome. This process begins in early stage of prophase I which is called leptotene.