Question

All of the following are effects of crossing over of homologous chromosomes during prophase I of meiosis with the EXCEPTION of A) increased genetic variety. B) increased number of chromosomes in the offspring. C) the appearance of new phenotypes in the offspring. D) possible harmful mutations from cross-over errors.

Answer 1

B) increased number of chromosomes in the offspring.

Step-by-step explanation:

Crossing over process occurs in germ cells in prophase I of meiosis I. In this process, non sister chromatids of homologous pair of chromosomes exchange their corresponding DNA segments with each other which leads to the generation of new combination of genes in the progenies. New combination of genes also means that the offsprings will not have traits exactly the same as that of either parent. The offsprings will have a combination of genes which are present in the parents. But, crossing over will not give rise to increased number of chromosomes in the off spring because they are simply exchanging the DNA segments. It means that if one of the homologous chromosomes is giving the DNA segment to another chromosome within the pair then it is also receiving the DNA segment from that chromosome so the loss is compensated.

Answer 2

Answer;

B) increased number of chromosomes in the offspring.

Explanation;

-Cross over is a process that takes place during meiosis. It occurs when homologous chromosomes pair up and the segments of chromosomes are exchanged between non sister chromatids, resulting to recombinant chromosomes.

-The process causes genetic variation among organisms due to exchange of genetic material. In addition to increased genetic variation, cross over may results to the appearance of new phenotypes in the offspring. Also cros-over mutations may cause harmful mutations.