Question

A. Which type of mutation do you feel would be most likely to be influenced by natural selection, those that result in changes of the third codon position, or those that result in changes of the first codon position? Explain your reasoning. B. In many animals inbreeding among close relatives reduces the ability of their offspring to survive. Explain why this occurs.

Answer 1

ANSWER A:

The errors caused by mutation are minimized due to the position dependant selection through natural selection process. The changes in third codon occur faster than the other two positions irrespective of the amino acid which is encoded by this codon. This gives rise to the synonymois substitutions. The third position sites are most variable and therefore vulnerable to changes due to Their GC and AT content. The changes in G occur the slowest when at the third position. However, due to more pyrimidines at thoird position most of the time, this site changes at the fastest rate. Hence, the mutations that result in changes of the third codon position are most likely to be influenced by natural selection? for reversal of the error caused.

ANSWER B:

The inbreeding among close relatives causes a bottle neck effect that stabilises alterations or mutation if any. These are then passed on from generations to generations. Hence, this inbreeding depression reduces the ability of their offspring to survive due to reduction in the genetic fitness.