scholarly journals A critical assessment of estimating census population size from genetic population size (or vice versa) in three fishes

2017 ◽  
Vol 10 (9) ◽  
pp. 935-945 ◽  
Author(s):  
Matthew Carl Yates ◽  
Thais A. Bernos ◽  
Dylan J. Fraser
Keyword(s):  
Population Size ◽  
Critical Assessment ◽  
Genetic Population ◽  
Census Population Size

scholarly journals Is genomic diversity a useful proxy for census population size? Evidence from a species‐rich community of desert lizards

2019 ◽  
Vol 28 (7) ◽  
pp. 1664-1674 ◽  
Author(s):  
Maggie R. Grundler ◽  
Sonal Singhal ◽  
Mark A. Cowan ◽  
Daniel L. Rabosky
Keyword(s):  
Population Size ◽  
Genomic Diversity ◽  
Census Population Size

scholarly journals Population size, habitat fragmentation, and the nature of adaptive variation in a stream fish

2014 ◽  
Vol 281 (1790) ◽  
pp. 20140370 ◽  
Author(s):  
Dylan J. Fraser ◽  
Paul V. Debes ◽  
Louis Bernatchez ◽  
Jeffrey A. Hutchings
Keyword(s):  
Genetic Variation ◽  
Habitat Fragmentation ◽  
Population Size ◽  
Brook Trout ◽  
Small Populations ◽  
Adaptive Genetic Variation ◽  
Genetic Population ◽  
Fragmented Populations ◽  
Large Populations ◽  
Adaptive Differentiation

Whether and how habitat fragmentation and population size jointly affect adaptive genetic variation and adaptive population differentiation are largely unexplored. Owing to pronounced genetic drift, small, fragmented populations are thought to exhibit reduced adaptive genetic variation relative to large populations. Yet fragmentation is known to increase variability within and among habitats as population size decreases. Such variability might instead favour the maintenance of adaptive polymorphisms and/or generate more variability in adaptive differentiation at smaller population size. We investigated these alternative hypotheses by analysing coding-gene, single-nucleotide polymorphisms associated with different biological functions in fragmented brook trout populations of variable sizes. Putative adaptive differentiation was greater between small and large populations or among small populations than among large populations. These trends were stronger for genetic population size measures than demographic ones and were present despite pronounced drift in small populations. Our results suggest that fragmentation affects natural selection and that the changes elicited in the adaptive genetic composition and differentiation of fragmented populations vary with population size. By generating more variable evolutionary responses, the alteration of selective pressures during habitat fragmentation may affect future population persistence independently of, and perhaps long before, the effects of demographic and genetic stochasticity are manifest.

scholarly journals Mitochondrial DNA Sequence Diversity in Mammals: A Correlation between the Effective and Census Population Sizes

2020 ◽  
Vol 12 (12) ◽  
pp. 2441-2449
Author(s):  
Jennifer James ◽  
Adam Eyre-Walker
Keyword(s):  
Mitochondrial Dna ◽  
Metabolic Rate ◽  
Population Size ◽  
Effective Population Size ◽  
Dna Sequence ◽  
Range Size ◽  
Effective Population ◽  
Population Sizes ◽  
Census Population Size ◽  
The Relationship

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.

scholarly journals Trade-offs in Robustness to Perturbations of Bacterial Population Controllers

2020 ◽  
Author(s):  
Cameron McBride ◽  
Domitilla Del Vecchio
Keyword(s):  
Population Size ◽  
Cell Population ◽  
Resource Sharing ◽  
Genetic Circuit ◽  
Genetic Circuits ◽  
Genetic Population ◽  
Considerable Difficulty ◽  
Trade Offs ◽  
Multiple Cell ◽  
Circuit Components

AbstractSynthetic biology applications have the potential to have lasting impact; however, there is considerable difficulty in scaling up engineered genetic circuits. One of the current hurdles is resource sharing, where different circuit components become implicitly coupled through the host cell’s pool of resources, which may destroy circuit function. One potential solution around this problem is to distribute genetic circuit components across multiple cell strains and control the cell population size using a population controller. In these situations, perturbations in the availability of cellular resources, such as due to resource sharing, will affect the performance of the population controller. In this work, we model a genetic population controller implemented by a genetic circuit while considering perturbations in the availability of cellular resources. We analyze how these intracellular perturbations and extracellular disturbances to cell growth affect cell population size. We find that it is not possible to tune the population controller’s gain such that the population density is robust to both extracellular disturbances and perturbations to the pool of available resources.

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
Keyword(s):  
Population Size ◽  
Size Ratio ◽  
Ratio Estimation ◽  
Census Population Size

scholarly journals Effective number of breeders, effective population size and their relationship with census size in an iteroparous species, Salvelinus fontinalis

2016 ◽  
Vol 283 (1823) ◽  
pp. 20152601 ◽  
Author(s):  
Daniel E. Ruzzante ◽  
Gregory R. McCracken ◽  
Samantha Parmelee ◽  
Kristen Hill ◽  
Amelia Corrigan ◽  
...  
Keyword(s):  
Population Dynamics ◽  
Population Size ◽  
Brook Trout ◽  
Overlapping Generations ◽  
Salvelinus Fontinalis ◽  
Effective Number ◽  
Effective Number Of Breeders ◽  
Unbiased Estimates ◽  
Census Population Size ◽  
The Relationship

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.

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