Question

In both mitosis and select answer a spindle forms and separates sister chromatids. While mitosis produces two nuclel, meiosis i produces select answer Which of the following is an outcome of crossing over? The formation of a zygote The production of gametes The introduction of novel combinations of alleles in offspring The production of genetically identical offspring

Answer 1

Ans:

In both mitosis and meiosis II, a spindle forms and separates sister chromatids. While mitosis produces two nuclei, meiosis II produces four nuclei.

Explanation: In both mitosis and meiosis II spindle fibres are attached to kinetochore and sister chromatids of the chromosome separates and moves to the opposite pole in anaphase and anaphase II. After mitosis, each parental cell produces two genetically identical daughter nuclei but after meiosis II, each parent cell produces four haploid daughter nuclei of different allelic combination.

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The introduction of novel combinations of alleles in offspring

Explanation: Crossing over is the physical exchange between non-sister chromatids of homologous chromosome. It occurs in the pachytene stage of meiosis I where a new novel combinations of alleles (recombinant genes) are formed by this process. Zygote is formed by a process called fertilization where male and female gametes are fused. Genetically identical offspring are produced in mitosis and when crossing over doesn't occur. Gametes is produced by a process called meiosis.

A b (non Meiosisi crossover) A A b & Meiasis o paren tal 3 B meiosis I VO A b Parental I Memos oss Meiosis B A B crossing over Recombinant a b Parental Scanned by TapScanner