Which process best explains genetic differences arising within a species during meiosis?

Which process best explains genetic differences arising within a species during meiosis?

• A. Fertilization
• B. Crossing over
• C. Zygote
• D. Haploid

Answer: (B)

Crossing over is the process that best explains new combinations of alleles arising during meiosis. In prophase I of meiosis, homologous chromosomes pair up and non-sister chromatids exchange genetic segments. This shuffle creates recombinant chromosomes, so the gametes produced carry novel allele combinations rather than the exact parental ones. This generates genetic diversity within the species before fertilization occurs. Fertilization is the union of two gametes to form a zygote, which increases variation at the population level but is not the meiotic mechanism that produces new allele arrangements. A zygote is the product of fertilization, not a process that creates variation during meiosis. Haploid describes the chromosome number of gametes, not a process.

Crossing over is the process that best explains new combinations of alleles arising during meiosis. In prophase I of meiosis, homologous chromosomes pair up and non-sister chromatids exchange genetic segments. This shuffle creates recombinant chromosomes, so the gametes produced carry novel allele combinations rather than the exact parental ones. This generates genetic diversity within the species before fertilization occurs.

Fertilization is the union of two gametes to form a zygote, which increases variation at the population level but is not the meiotic mechanism that produces new allele arrangements. A zygote is the product of fertilization, not a process that creates variation during meiosis. Haploid describes the chromosome number of gametes, not a process.