scholarly journals Effective/census population size ratio estimation: a compendium and appraisal

2012 ◽  
Vol 2 (9) ◽  
pp. 2357-2365 ◽  
Author(s):  
Friso P. Palstra ◽  
Dylan J. Fraser
2019 ◽  
Vol 28 (7) ◽  
pp. 1664-1674 ◽  
Author(s):  
Maggie R. Grundler ◽  
Sonal Singhal ◽  
Mark A. Cowan ◽  
Daniel L. Rabosky

2020 ◽  
Vol 12 (12) ◽  
pp. 2441-2449
Author(s):  
Jennifer James ◽  
Adam Eyre-Walker

Abstract What determines the level of genetic diversity of a species remains one of the enduring problems of population genetics. Because neutral diversity depends upon the product of the effective population size and mutation rate, there is an expectation that diversity should be correlated to measures of census population size. This correlation is often observed for nuclear but not for mitochondrial DNA. Here, we revisit the question of whether mitochondrial DNA sequence diversity is correlated to census population size by compiling the largest data set to date, using 639 mammalian species. In a multiple regression, we find that nucleotide diversity is significantly correlated to both range size and mass-specific metabolic rate, but not a variety of other factors. We also find that a measure of the effective population size, the ratio of nonsynonymous to synonymous diversity, is also significantly negatively correlated to both range size and mass-specific metabolic rate. These results together suggest that species with larger ranges have larger effective population sizes. The slope of the relationship between diversity and range is such that doubling the range increases diversity by 12–20%, providing one of the first quantifications of the relationship between diversity and the census population size.


2016 ◽  
Vol 283 (1823) ◽  
pp. 20152601 ◽  
Author(s):  
Daniel E. Ruzzante ◽  
Gregory R. McCracken ◽  
Samantha Parmelee ◽  
Kristen Hill ◽  
Amelia Corrigan ◽  
...  

The relationship between the effective number of breeders ( N b ) and the generational effective size ( N e ) has rarely been examined empirically in species with overlapping generations and iteroparity. Based on a suite of 11 microsatellite markers, we examine the relationship between N b , N e and census population size ( N c ) in 14 brook trout ( Salvelinus fontinalis ) populations inhabiting 12 small streams in Nova Scotia and sampled at least twice between 2009 and 2015. Unbiased estimates of N b obtained with individuals of a single cohort, adjusted on the basis of age at first maturation ( α ) and adult lifespan (AL), were from 1.66 to 0.24 times the average estimates of N e obtained with random samples of individuals of mixed ages (i.e. ). In turn, these differences led to adjusted N e estimates that were from nearly five to 0.7 times the estimates derived from mixed-aged individuals. These differences translate into the same range of variation in the ratio of effective to census population size within populations. Adopting as the more precise and unbiased estimates, we found that these brook trout populations differ markedly in their effective to census population sizes (range approx. 0.3 to approx. 0.01). Using A ge N e , we then showed that the variance in reproductive success or reproductive skew varied among populations by a factor of 40, from V k / k ≈ 5 to 200. These results suggest wide differences in population dynamics, probably resulting from differences in productivity affecting the intensity of competition for access to mates or redds, and thus reproductive skew. Understanding the relationship between N e , N b and N c , and how these relate to population dynamics and fluctuations in population size, are important for the design of robust conservation strategies in small populations with overlapping generations and iteroparity.


Author(s):  
Jennifer James ◽  
Adam Eyre-Walker

AbstractWhat determines the level of genetic diversity of a species remains one of the enduring problems of population genetics. Since, neutral diversity depends upon the product of the effective population size and mutation rate there is an expectation that diversity should be correlated to measures of census population size. This correlation is often observed for nuclear but not for mitochondrial DNA. Here we revisit the question of whether mitochondrial DNA sequence diversity is correlated to census population size by compiling the largest dataset to date from 639 mammalian species. In a multiple regression we find that nucleotide diversity is significantly correlated to both range size and mass-specific metabolic rate, but not a variety of other factors. We also find that a measure of the effective population size, the ratio of non-synonymous to synonymous diversity, is also significantly negatively correlated to both range and mass-specific metabolic rate. These results together suggest that species with larger ranges have larger effective population sizes. The slope of the relationship between diversity and range is such that doubling the range increases diversity by 12 to 20%, providing one of the first quantifications of the relationship between effective and census population sizes.


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