This could reflect strong directional selection acting in this ESU drawing the LehoDAB*74 allele close to fixation, or a depletion in DAB diversity due to population decline or bottleneck.
Sharp population declines, or bottlenecks, like those seen during the recent El Niños, may translate into losses of genetic variation that can lead to increased rates of inbreeding and the fixation of deleterious alleles, and hinder the ability of populations to adapt to future changes in the environment [18] [20].
Perhaps a more attractive version of the Diaz-Alejandro hypothesis assigns Argentina's relative decline to the bottlenecks in foreign trade (produced by excessive aversion to trade with other countries), the large fiscal imbalances (produced by an underestimation of the costs of inflation) and the instability that some of Peron's redistributive policies induced.
Theory [36], [37] and observations on natural avian systems [38], [39] suggest that bottlenecks, such as those experienced upon colonization of an island, are most likely to decrease allelic diversity (due to the loss of rare alleles) while heterozygosity will decline only if the bottleneck is severe and the growth rate of the population is low.
Results gathered from the condor studies will help identify recovery options for other at-risk species as their populations continue to decline and experience genetic bottlenecks.
This seasonal dynamic is consistent with that observed in a semi-natural habitat, such as a compost heap, where C. elegans population size varies over the year, from a dense population in autumn to one that declines and undergoes bottlenecks in winter (Barrière and Félix, 2007; Petersen et al., 2014).
These leopard populations have not evolved in isolation due to genetic drift, and we did not detect any indication of this population having gone through any severe population decline leading to a genetic bottleneck.
Using computer simulations, Antao et al. (2010) evaluated the ability of NeD and NeV estimators to (i) detect a population decline, (ii) correctly identify a bottleneck with low bias and high precision, and (iii) evaluate whether the methods were subject to a high rate of false positives (i.e., indicate a bottleneck when none had occurred).
This situation can be described as queuing behind a bottleneck whose capacity declines when the queue is large.
However, according to Amdahl's law, it has a bottleneck of gradually declining parallel speedup ratio as the number of computing nodes increases.
