MVP and Genetic variation

MVP and Genetic variation - 0.05 to 1.0). This means that...

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MVP and Genetic variation Population genetic theory indicates that inbreeding depression will be likely with an effective population size of N e < 50. To avoid the possibility of inbreeding, a lower limit of MVP = 500 . These numbers may seem like obscure conclusions from a series of complex Populus simulations, but they are the working numbers for policy issues : N = 50 defines the critical list; N = 500 defines the endangered list . The values for MVP and "critical" versus "endangered" lists stem from some basic issues relating to effective population size. N e refers to the effective number of breeders in the population, and can be affected greatly by variance in reproductive success A focus here is the ratio of effective size to census size N e /N ratio . Observations from field and laboratory experiments indicate that N e /N ratios are about 0.25 (range =
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Unformatted text preview: 0.05 to 1.0). This means that either some individuals are breeding and others are not, or that some individuals have different degrees reproductive success that others. It is possible that a substantial proportion of the population does reproduce, but that a small number of individuals produce most of offspring reducing the genetic pool from which alleles are drawn. This reduces the N e /N ratio and hence brings the population closer to the demographic danger zone. With a N e /N ratio of 0.25, the census size should be 4 times higher than the simple numbers predicted by "critical" and "endangered" estimates. Now add population size fluctuations: bottlenecks in census size affect N e more severely. Recall: = (1/N e ) = (1/t) (1/N e ) The net effect of these factors is that MVP should be 5X to 10X N e ....
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This note was uploaded on 11/06/2011 for the course BIO BSC1010 taught by Professor Gwenhauner during the Fall '10 term at Broward College.

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