Question

This are the questions you need to answer:

In mammals, males often have greater variance in reproductive success than females, as a result of sexual selection.

How will this alter the effective levels of allelic variation in genes on the autosomes, the X chromosome, the Y chromosome and the mitochondrial genome?

What other factors may influence the genetic diversity in these different parts of the genome?

Discuss this question and potential answers with one another by posting your answers on the forum.

Just in order to prime this discussion, think about this:

If fewer males reproduce than females, what effects will this have on y-chromosome diversity vs. mitochondrial diversity? Variance in reproductive success means basically "Some guys have all the luck". What would be the influence of this type of selection on x-chromosomes diversity or autosomal diversity? Are there other things that can happen to a population which affect genetic diversity? Would you have different conclusions about how and when our species evolved from the different levels of diversity seen using Y Chromosomes, X Chromosomes, and Mitochondrial Chromosomes?

Answer 1

• In mammals, male often have greater variance in reproductive success than females due to presence of Y - chromosomes in their allosomes/ sex chromosomes, result in sexual selection.
• Allelic variation is define as the number of different alleles( alternative form of character) forms at a particular locus.
• In autosomes , their is no effect of allelic variation as autosomes have no X and Y chromosomes.
• The X - chromosomes and the Y - chromosomes can alter the effective level of allelic variation because they are present in allosomes/ sex determining chromosomes. And can show allelic variation, thus can result in genetic diversity.
• Mitochondrial genome have no such role. As they are self replicating bodies.
• Genetic variation or genetic diversity means the diversity or variation that exist in genome of individual with population. Beside allelic variation, the other factors that influences the genetic variations are:-

1. Mutation ( Changes in DNA sequence)

2. Random mating and fertilization between the organisms.

3. Recombination or crossing over between the chromatids of homologous chromosomes during meiosis ( reductional division)

• If fewer male reproduces than females, both male and female contributes to 50:50 to next generation, the contribution of male is all from just a single male. So, the next generation would have all the same Y chromosomes. And about Mitochondrial DNA, the all different sets appear in next generation as it solely pass from maternal side.
• x- chromosome and autosomes influences more in genetic diversity than Y chromosomes because Y chromosome is only found in male so it has less sites for genetic recombination and hence less influences the genetic recombination.
• Other things that can happen to a population and affect genetic diversity are mating between close relatives influences less the genetic diversity and vice-versa.
• No such true evident is being concluded that how and when our species evolved from different levels of diversity.