Genetic Drift - Essay Example

Evolution according to Darwin is by natural selection. A biological process of gene adjustment throughout generations depends on factors that support life. Since natural selection depends on physical gene makeup. A process that relies on the possibilities of events on genotype selection for the development of a beneficial trait for survival. Therefore, evolution is all about random genotype selections; whereas probability is a measure of how likely it is that an event will happen. Therefore both probability and evolutions are about the likeliness of events occurring. In a genetic variation, probability measures the possible gene variations that may occur in the future generation.
In the genetic drift process, rapid change in gene variation is readily noticeable in small reproductive isolated populations. (Zimmer & Emlen, 2013). A smaller population is more affected by genetic drift due to fewer alleles to balance out the effect of random changes. A small population also increases the likelihood of inbreeding which negatively affects the changes in allele frequencies over time, allowing recessive genes to be dominant over a small population hence causing rapid genetic variation. For example, from the above experiment, there is an explicit indication of abnormal frequency outcomes from two flip coin results compared to fifty flip coin results.
Factors affecting Allele frequencies: various factors can cause the dominance of alleles in a given population. These factors include genetic isolation which refers to the separation of potentially interbreeding animals. This condition reduces the chances of balancing allele frequency by facilitating the development of a less dominant allele in the future generation. Selective sexual selection affects the allele frequency where only particular phenotypes get selected by mates. The allele of the chosen ones increases in frequency and those not chosen will decrease. For example in peacocks, fancy feathers males are chosen to reproduce. Another factor is the genetic drift that occurs in small populations. Chance, mating, or luck can dramatically change the frequency of alleles in the small gene pool.
Buri experiment: He set up over 100 replicate populations of 16 Drosophila flies and follows each population for many generations to measure variation in allele frequency. All of the population used in the experiment began with 8 males and 8 females that were all heterozygous for an eye color mutation. Drosophila eye coloration for genotype was easily observed. He took 3 different genotypes which included homozygote for the mutant bw allele for white eyes, homozygote for the bw 75 allele for bright red eyes, and the heterozygote allele had light orange eyes. Each generation had 8 males and 8 females in his sample; he then recorded the number of eye-color genotypes and used them as parents to reproduce for the next generation. Genetic drift is responsible for changes in allele frequency. From Buri’s experiment, it is evident that genetic drift can change allele frequency in a population from 0 to 1 depending on various factors such as selective breeding selection, natural selection, and other factors.
The column frequency at 0 and 1 continues to grow higher due to rapid changes in the frequency of a particular allele in every new generation. Genetic variation causes an increase in the frequency column. In this process, one type of allele will dominate the other due to favorite conditions for its existence. The process can’t be reversed since the other allele careers may be experiencing permanent harsh conditions for survival hence facilitating the rapid increase of the dominant allele. Therefore, resulting in the extinction of less dominant alleles in generations to come. Read More