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Polymorphism data can reveal the origin of species abundance statistics.

Maruvka YE, Shnerb NM - PLoS Comput. Biol. (2009)

Bottom Line: A statistical test, based on the Fu-Li method, has been developed and enables such a differentiation.We have analyzed the results gathered from individual-based simulation of both types of histories and obtained clear distinction between the Fu-Li statistics of the neutral scenario and that of the niche scenario.Our results suggest that data for 10-50 species, with approximately 30 sequenced individuals for each species, may allow one to distinguish between these two theories.

View Article: PubMed Central - PubMed

Affiliation: Physics Department, Bar-Ilan University, Ramat-Gan, Israel. yosi.maruvka@gmail.com

ABSTRACT
What is the underlying mechanism behind the fat-tailed statistics observed for species abundance distributions? The two main hypotheses in the field are the adaptive (niche) theories, where species abundance reflects its fitness, and the neutral theory that assumes demographic stochasticity as the main factor determining community structure. Both explanations suggest quite similar species-abundance distributions, but very different histories: niche scenarios assume that a species population in the past was similar to the observed one, while neutral scenarios are characterized by strongly fluctuating populations. Since the genetic variations within a population depend on its abundance in the past, we present here a way to discriminate between the theories using the genetic diversity of noncoding DNA. A statistical test, based on the Fu-Li method, has been developed and enables such a differentiation. We have analyzed the results gathered from individual-based simulation of both types of histories and obtained clear distinction between the Fu-Li statistics of the neutral scenario and that of the niche scenario. Our results suggest that data for 10-50 species, with approximately 30 sequenced individuals for each species, may allow one to distinguish between these two theories.

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Fu-Li F-Statistics.The distributions of the Fu-Li F-Statistics for the two different scenarios are presented. The full lines correspond to histories that obey the rules of the niche history, while the dashed lines represent the statistics gathered from neutral histories. Several current population sizes are presented. Current population size  is represented by black circles,  by blue squares, 10000 by magenta+signs, and  by green diamonds. It can be seen that there is almost no difference between current population sizes with the same history; the entire discrepancy is between the two scenarios. Every distribution was produced by 3000–5000 realizations, and from every realization  individuals were sampled. In fact, only when we decreased the sample size to 10 individuals per species did the statistical measure really fail.
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pcbi-1000359-g002: Fu-Li F-Statistics.The distributions of the Fu-Li F-Statistics for the two different scenarios are presented. The full lines correspond to histories that obey the rules of the niche history, while the dashed lines represent the statistics gathered from neutral histories. Several current population sizes are presented. Current population size is represented by black circles, by blue squares, 10000 by magenta+signs, and by green diamonds. It can be seen that there is almost no difference between current population sizes with the same history; the entire discrepancy is between the two scenarios. Every distribution was produced by 3000–5000 realizations, and from every realization individuals were sampled. In fact, only when we decreased the sample size to 10 individuals per species did the statistical measure really fail.

Mentions: We performed many numerical experiments simulating the niche scenario and the neutral scenario, and calculated the F-Statistic for each realization. We then produced the probability distribution of the F-Statistic for the two types of histories. As can be seen in Figure 2 the F-statistic differs in the two scenarios; both the width of the distribution and its average are not the same, as expected. An important feature of these statistics is that they do not depend on the species' abundance, only on their history.


Polymorphism data can reveal the origin of species abundance statistics.

Maruvka YE, Shnerb NM - PLoS Comput. Biol. (2009)

Fu-Li F-Statistics.The distributions of the Fu-Li F-Statistics for the two different scenarios are presented. The full lines correspond to histories that obey the rules of the niche history, while the dashed lines represent the statistics gathered from neutral histories. Several current population sizes are presented. Current population size  is represented by black circles,  by blue squares, 10000 by magenta+signs, and  by green diamonds. It can be seen that there is almost no difference between current population sizes with the same history; the entire discrepancy is between the two scenarios. Every distribution was produced by 3000–5000 realizations, and from every realization  individuals were sampled. In fact, only when we decreased the sample size to 10 individuals per species did the statistical measure really fail.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2667257&req=5

pcbi-1000359-g002: Fu-Li F-Statistics.The distributions of the Fu-Li F-Statistics for the two different scenarios are presented. The full lines correspond to histories that obey the rules of the niche history, while the dashed lines represent the statistics gathered from neutral histories. Several current population sizes are presented. Current population size is represented by black circles, by blue squares, 10000 by magenta+signs, and by green diamonds. It can be seen that there is almost no difference between current population sizes with the same history; the entire discrepancy is between the two scenarios. Every distribution was produced by 3000–5000 realizations, and from every realization individuals were sampled. In fact, only when we decreased the sample size to 10 individuals per species did the statistical measure really fail.
Mentions: We performed many numerical experiments simulating the niche scenario and the neutral scenario, and calculated the F-Statistic for each realization. We then produced the probability distribution of the F-Statistic for the two types of histories. As can be seen in Figure 2 the F-statistic differs in the two scenarios; both the width of the distribution and its average are not the same, as expected. An important feature of these statistics is that they do not depend on the species' abundance, only on their history.

Bottom Line: A statistical test, based on the Fu-Li method, has been developed and enables such a differentiation.We have analyzed the results gathered from individual-based simulation of both types of histories and obtained clear distinction between the Fu-Li statistics of the neutral scenario and that of the niche scenario.Our results suggest that data for 10-50 species, with approximately 30 sequenced individuals for each species, may allow one to distinguish between these two theories.

View Article: PubMed Central - PubMed

Affiliation: Physics Department, Bar-Ilan University, Ramat-Gan, Israel. yosi.maruvka@gmail.com

ABSTRACT
What is the underlying mechanism behind the fat-tailed statistics observed for species abundance distributions? The two main hypotheses in the field are the adaptive (niche) theories, where species abundance reflects its fitness, and the neutral theory that assumes demographic stochasticity as the main factor determining community structure. Both explanations suggest quite similar species-abundance distributions, but very different histories: niche scenarios assume that a species population in the past was similar to the observed one, while neutral scenarios are characterized by strongly fluctuating populations. Since the genetic variations within a population depend on its abundance in the past, we present here a way to discriminate between the theories using the genetic diversity of noncoding DNA. A statistical test, based on the Fu-Li method, has been developed and enables such a differentiation. We have analyzed the results gathered from individual-based simulation of both types of histories and obtained clear distinction between the Fu-Li statistics of the neutral scenario and that of the niche scenario. Our results suggest that data for 10-50 species, with approximately 30 sequenced individuals for each species, may allow one to distinguish between these two theories.

Show MeSH