Paternity Testing Research Today is a free monthly online journal that collates and summarizes the latest research about Paternity Testing, including details on accuracy, methods, procedure, dna testing.

Estimating genetic benefits of polyandry from experimental studies: a meta-analysis.

Slatyer RA, Mautz BS, Backwell PR, Jennions MD

Evolution, Ecology & Genetics, Research School of Biology, The Australian National University, Canberra, ACT 0200, Australia.

The consequences of polyandry for female fitness are controversial. Sexual conflict studies and a meta-analysis of mating rates in insects suggest that there is a longevity cost when females mate repeatedly. Even so, compensatory material benefits can elevate egg production and fertility, partly because polyandry ensures an adequate sperm supply. Polyandry can therefore confer direct benefits. The main controversy surrounds genetic benefits. The argument is analogous to that surrounding the evolution of conventional female mate choice, except that with polyandry it is post-copulatory mechanisms that might bias paternity towards males with higher breeding values for fitness. Recent meta-analyses of extra-pair copulations in birds have cast doubt on whether detectable genetic benefits exist. By contrast, another meta-analysis showed that polyandry elevates egg hatching success (possibly due to a fertilization bias towards sperm with paternal genes that elevate embryo survival) in insects. A detailed summary of whether polyandry elevates other components of offspring performance is lacking. Here we present a comprehensive meta-analysis of 232 effect sizes from 46 experimental studies. These experiments were specifically designed to try to quantify the potential genetic benefits of polyandry by controlling fully for the number of matings by females assigned to monandry and polyandry treatments. The bias-corrected 95% confidence intervals for egg hatching success (d = -0.01 to 0.61), clutch production (d = 0.07 to 0.45) and fertility (d = 0.04 to 0.40) all suggest that polyandry has a beneficial effect (although P values from parametric tests were marginally non-significant at P = 0.075, 0.052 and 0.058, respectively). Polyandry was not significantly beneficial for any single offspring performance trait (e.g. growth rate, survival, adult size), but the test power was low due to small sample sizes (suggesting that many more studies are still needed). We then calculated a composite effect size that provides an index of general offspring performance. Depending on the model assumptions, the mean effect of polyandry was either significantly positive or marginally non-significant. A possible role for publication bias is discussed. The magnitude of the reported potential genetic benefits (d = 0.07 to 0.19) are larger than those from two recent meta-analyses comparing offspring sired by social and extra-pair mates in birds (d = 0.02 to 0.04). This difference raises the intriguing possibility that cryptic, post-copulatory female choice might be more likely to generate 'good gene' or 'compatible gene' benefits than female choice of mates based on the expression of secondary sexual traits.

Published 6 May 2011 in Biol Rev Camb Philos Soc.
Full-text of this article is available online (may require subscription).

Articles on Paternity Testing published 7 April 2011:

Genetic polymorphism analysis of 15 STR loci in Chinese Hui ethnic group residing in Qinghai province of China.   Mol Biol Rep, 38(4): 2315-22.

In the present study, we investigated the diversity distributions of allelic frequencies of 15 short tandem repeats (STRs) loci in a sample of Chinese Hui ethnic group in the Ningxia Hui Autonomous Region. The allelic frequencies of the 15 STR loci (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818 and FGA) were obtained from 2975 unrelated healthy Hui individuals. The STR genotyping data of all the samples were generated by DNA ... [Abstract] [Full-text]

Genetic polymorphism analysis of 15 STR loci in Chinese Hui ethnic group residing in Qinghai province of China.   Mol Biol Rep, 38(4): 2315-22.

In the present study, we investigated the diversity distributions of allelic frequencies of 15 short tandem repeats (STRs) loci in a sample of Chinese Hui ethnic group in the Ningxia Hui Autonomous Region. The allelic frequencies of the 15 STR loci (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818 and FGA) were obtained from 2975 unrelated healthy Hui individuals. The STR genotyping data of all the samples were generated by DNA ... [Abstract] [Full-text]

Genetic polymorphism analysis of 15 STR loci in Chinese Hui ethnic group residing in Qinghai province of China.   Mol Biol Rep, 38(4): 2315-22.

In the present study, we investigated the diversity distributions of allelic frequencies of 15 short tandem repeats (STRs) loci in a sample of Chinese Hui ethnic group in the Ningxia Hui Autonomous Region. The allelic frequencies of the 15 STR loci (D8S1179, D21S11, D7S820, CSF1PO, D3S1358, TH01, D13S317, D16S539, D2S1338, D19S433, vWA, TPOX, D18S51, D5S818 and FGA) were obtained from 2975 unrelated healthy Hui individuals. The STR genotyping data of all the samples were generated by DNA ... [Abstract] [Full-text]

Articles on Paternity Testing published 14 March 2011:

The influence of maternal effects on indirect benefits associated with polyandry.   Proc Biol Sci, 278(1709): 1177-82.

Despite numerous and diverse theoretical models for the indirect benefits of polyandry, empirical support is mixed. One reason for the difficulty in detecting indirect benefits of polyandry may be that these are subtle and are mediated by environmental effects, such as maternal effects. Maternal effects may be especially important if females allocate resources to their offspring depending on the characteristics of their mating partners. We test this hypothesis in the burying beetle Nicrophorus ... [Abstract] [Full-text]

The influence of maternal effects on indirect benefits associated with polyandry.   Proc Biol Sci, 278(1709): 1177-82.

Despite numerous and diverse theoretical models for the indirect benefits of polyandry, empirical support is mixed. One reason for the difficulty in detecting indirect benefits of polyandry may be that these are subtle and are mediated by environmental effects, such as maternal effects. Maternal effects may be especially important if females allocate resources to their offspring depending on the characteristics of their mating partners. We test this hypothesis in the burying beetle Nicrophorus ... [Abstract] [Full-text]

Articles on Paternity Testing published 10 March 2011:

Sex-specific differential survival of extra-pair and within-pair offspring in song sparrows, Melospiza melodia.   Proc Biol Sci.

It is widely hypothesized that the evolution of female extra-pair reproduction in socially monogamous species reflects indirect genetic benefits to females. However, a critical prediction of this hypothesis, that extra-pair young (EPY) are fitter than within-pair young (WPY), has rarely been rigorously tested. We used 18 years of data from free-living song sparrows, Melospiza melodia, to test whether survival through major life-history stages differed between EPY and WPY maternal half-siblings. ... [Abstract] [Full-text]

Sex-specific differential survival of extra-pair and within-pair offspring in song sparrows, Melospiza melodia.   Proc Biol Sci.

It is widely hypothesized that the evolution of female extra-pair reproduction in socially monogamous species reflects indirect genetic benefits to females. However, a critical prediction of this hypothesis, that extra-pair young (EPY) are fitter than within-pair young (WPY), has rarely been rigorously tested. We used 18 years of data from free-living song sparrows, Melospiza melodia, to test whether survival through major life-history stages differed between EPY and WPY maternal half-siblings. ... [Abstract] [Full-text]

Sex-specific differential survival of extra-pair and within-pair offspring in song sparrows, Melospiza melodia.   Proc Biol Sci.

It is widely hypothesized that the evolution of female extra-pair reproduction in socially monogamous species reflects indirect genetic benefits to females. However, a critical prediction of this hypothesis, that extra-pair young (EPY) are fitter than within-pair young (WPY), has rarely been rigorously tested. We used 18 years of data from free-living song sparrows, Melospiza melodia, to test whether survival through major life-history stages differed between EPY and WPY maternal half-siblings. ... [Abstract] [Full-text]

© 2004-2011 Paternity Testing Research Today. All Rights Reserved.