When a few individuals form a new colony and these individuals have less genetic diversity than the original population this is called the?
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journal article Evolution Vol. 29, No. 1 (Mar., 1975) , pp. 1-10 (10 pages) Published By: Society for the Study of Evolution https://doi.org/10.2307/2407137 https://www.jstor.org/stable/2407137 Read and download Log in through your school or library Alternate access options For independent researchers Read Online Read 100 articles/month free Subscribe to JPASS Unlimited reading + 10 downloads Purchase article $4.00 - Download now and later Abstract When a population goes through a small bottleneck, the genetic variability of the population is expected to decline rapidly but, as soon as population size becomes large, it starts to increase owing to new mutations. This problem is studied mathematically, and the results obtained indicate that the amount of reduction in average heterozygosity per locus depends not only on the 'size of bottleneck' but also on the rate of population growth. If population size increases rapidly after going through a bottleneck, the reduction in average heterozygosity is rather small even if bottleneck size is extremely small. On the other hand, the loss in the average number of alleles per locus is profoundly affected by bottleneck size but not so much by the rate of population growth. This difference occurs mainly because random genetic drift eliminates many low frequency alleles. However, the average number of alleles per locus increases faster than the average heterozygosity when population size is restored. Application of the theory developed to the Bogota population of Drosophila pseudoobscura supports Prakash's postulate that this population has grown very rapidly, starting from a few migrants from a Central or North American population. Journal Information Evolution, published for the Society for the Study of Evolution, is the premier publication devoted to the study of organic evolution and the integration of the various fields of science concerned with evolution. The journal presents significant and original results that extend our understanding of evolutionary phenomena and processes. Rights & Usage This item is part of a JSTOR Collection. Eastern Pennsylvania is home to beautiful farmlands and countryside, but it's also a gold mine of information for geneticists, who have studied the region's Amish culture for decades. Because of their closed population stemming from a small number of German immigrants -- about 200 individuals -- the Amish carry unusual concentrations of gene mutations that cause a number of otherwise rare inherited disorders, including forms of dwarfism. One form of dwarfism, Ellis-van Creveld syndrome, involves not only short stature but polydactyly (extra fingers or toes), abnormalities of the nails and teeth, and, in about half of individuals, a hole between the two upper chambers of the heart. The syndrome is common in the Amish because of the "founder effect." When a small part of a population moves to a new locale, or when the population is reduced to a small size because of some environmental change, the genes of the "founders" of the new society are disproportionately frequent in the resulting population. If individuals in the group tend to marry within it, there's a greater likelihood that the recessive genes of the founders will come together in the cells that produce offspring. Thus diseases of recessive genes, which require two copies of the gene to cause the disease, will show up more frequently than they would if the population married outside the group. In the Amish, in fact, Ellis-van Creveld syndrome has been traced back to one couple, Samuel King and his wife, who came to the area in 1744. The mutated gene that causes the syndrome was passed along from the Kings and their offspring, and today it is many times more common in the Amish population than in the American population at large. The founder effect is an extreme example of "genetic drift." Genes occurring at a certain frequency in the larger population will occur at a different frequency -- more or less often -- in a smaller subset of that population. As in the example of human diseases, genetically determined traits that would ordinarily be uncommon in the overall gene pool might crop up with distressing frequency in a small subset of that pool. What happens if there is less genetic diversity?If genetic diversity gets too low, species can go extinct and be lost forever. This is due to the combined effects of inbreeding depression and failure to adapt to change. In such cases, the introduction of new alleles can save a population. This is called genetic rescue [2].
Why do small populations have less genetic diversity?Small populations tend to lose genetic diversity more quickly than large populations due to stochastic sampling error (i.e., genetic drift). This is because some versions of a gene can be lost due to random chance, and this is more likely to occur when populations are small.
When individuals from one population move to another population and breed it is an example of?Migration. Migration is the movement of organisms from one location to another. Although it can occur in cyclical patterns (as it does in birds), migration when used in a population genetics context often refers to the movement of individuals into or out of a defined population.
What type of genetic drift results from the colonization of a new location by a small number of individuals?The founder effect is a special case of genetic drift, occurring when a small group in a population splinters off from the original population and forms a new one.
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