Population and Conservation Genetics of Marsupials

1989 ◽  
Vol 37 (3) ◽  
pp. 161 ◽  
Author(s):  
WB Sherwin ◽  
ND Murray
Keyword(s):  
Population Genetics ◽  
Conservation Genetics ◽  
Current Knowledge ◽  
Effective Size ◽  
Individual Species ◽  
Census Size ◽  
Electrophoretic Data ◽  
Marsupial Species ◽  
Small Effective Size ◽  
Census Number

This article summarises current knowledge of marsupial population genetics, and discusses its relevance to the conservation of marsupial species. It has been suggested that there is much lower genetic variation within marsupial populations than in eutherian mammals. This trend is not evident in the electrophoretic data summarised here. However, genetic differentiation between populations, subspecies, and species of marsupials appears to be slightly lower than comparable values for eutherians. Genetic estimates of migration between populations are scarce at present, but show values that are comparable with eutherians. Some studies of marsupial population genetics have used non-electrophoretic characteristics, or have addressed the possibility of selection on the characters analysed. Although few, these studies indicate the suitability of marsupials for such investigations. Recent debate over the theories and applications of conservation genetics has made it clear that more research is required on individual species. Given the record of extinction of marsupials in the last 200 years, it is important to test the applicability of these theories to individual marsupial species. Several examples are discussed emphasising the need for ecological studies that estimate the effective number of reproducing individuals per generation. This figure, called the effective size, is the corner- stone of conservation genetics theory, being an important determinant of both the rate of loss of variation between individuals, and the rate of inbreeding. The effective size of the mainland population of the eastern barred bandicoot, Perameles gunnii, appears to be only about one-tenth of its census number. This result is comparable with estimates made in other vertebrates, and demonstrates that many marsupial species which appear to have an adequate census size on ecological grounds may face genetic problems resulting from small effective size.

scholarly journals The population genetics of haplo-diploids and X-linked genes

1984 ◽  
Vol 44 (3) ◽  
pp. 321-341 ◽  
Author(s):  
P. J. Avery
Keyword(s):  
Population Genetics ◽  
Genetic Variability ◽  
Population Size ◽  
Effective Population Size ◽  
Disease Genes ◽  
Effective Population ◽  
Random Drift ◽  
Mutation Pressure ◽  
Electrophoretic Data ◽  
Fitness Parameters

SUMMARYFrom the available electrophoretic data, it is clear that haplodiploid insects have a much lower level of genetic variability than diploid insects, a difference that is only partially explained by the social structure of some haplodiploid species. The data comparing X-linked genes and autosomal genes in the same species is much more sparse and little can be inferred from it. This data is compared with theoretical analyses of X-linked genes and genes in haplodiploids. (The theoretical population genetics of X-linked genes and genes in haplodiploids are identical.) X-linked genes under directional selection will be lost or fixed more quickly than autosomal genes as selection acts more directly on X-linked genes and the effective population size is smaller. However, deleterious disease genes, maintained by mutation pressure, will give higher disease incidences at X-linked loci and hence rare mutants are easier to detect at X-linked loci. Considering the forces which can maintain balanced polymorphisms, there are much stronger restrictions on the fitness parameters at X-linked loci than at autosomal loci if genetic variability is to be maintained, and thus fewer polymorphic loci are to be expected on the X-chromosome and in haplodiploids. However, the mutation-random drift hypothesis also leads to the expectation of lower heterozygosity due to the decrease in effective population size. Thus the theoretical results fit in with the data but it is still subject to argument whether selection or mutation-random drift are maintaining most of the genetic variability at X-linked genes and genes in haplodiploids.

scholarly journals Energy value of meat in selected species of feathered game

2011 ◽  
Vol 80 (2) ◽  
pp. 197-202 ◽  
Author(s):  
František Vitula ◽  
Pavel Suchý ◽  
Eva Straková ◽  
Kateřina Karásková ◽  
David Zapletal ◽  
...  
Keyword(s):  
Japanese Quail ◽  
Dry Matter ◽  
Current Knowledge ◽  
Energy Content ◽  
Correlation Coefficients ◽  
Individual Species ◽  
Wild Turkey ◽  
Calorimetric Analysis ◽  
Grey Partridge ◽  
Thigh Muscles

The aim of this work was to compare gross energy (GE) in breast and thigh muscles in the following six species of feathered game reared in Europe: guineafowl (Numida meleagris), common pheasant (Phasianus colchicus), Japanese quail (Coturnix coturnix japonica), chukar (Alectoris chucar), grey partridge (Perdix perdix) and wild turkey (Meleagris gallopavo). Calorimetric analysis revealed significant (P ≤ 0.05) and highly significant (P ≤ 0.01) differences between individual species in the content of energy in breast and thigh muscles. The highest content of energy (recalculated to dry matter) was found in breast muscles from wild turkey (24.75 MJ·kg-1) and Japanese quail (24.57 MJ·kg-1) whereas the highest content of energy (recalculated to dry matter) in thigh muscles was found in Japanese quail and grey partridge. Highly significant (P ≤ 0.01) differences in the energy content were also found between breast and thigh muscles in all studied game species except for wild turkey. Differences in the content of energy in muscles between individual species occur mainly due to different contents of fat in muscles. This is also confirmed by high correlation coefficients between the content of energy and the content of fat in breast (r = 0.912) and thigh muscles (r = 0.878). Our study provides more specific data on the amount of energy in muscles of major species of feathered game reared in Europe and significantly extends current knowledge in this field.

scholarly journals EFFECTIVE SIZE OF AUTO-TETRAPLOID POPULATION UNDER PARTIAL SELFING

2015 ◽  
Vol 24 (1) ◽  
pp. 31
Author(s):  
Muhamad Sabran
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Numerical Study ◽  
Effective Size ◽  
Double Reduction ◽  
Effective Population ◽  
Census Size ◽  
Sister Chromatids ◽  
Tetraploid Population ◽  
Arbitrary Rate

Effective population size is defined as the number of breeding individual in an idealized population that would show the same amount of dispersion of allele frequencies under random genetic drift or the same amount of inbreeding as the population under consideration. Effective population size depends on the census size of the population and the mating system. In autotetraploid population, effective population size also depends on the probability of double reduction, i.e., a meiotic event when two sister chromatids end in the same gamete. In this research, we will study the effect of the probability of double reduction on the effective size of autotetraploid population reproduced by partial selfing. The formula for the effective population size was derived by equating the variance of the change in gene frequency in idealized population and its value in the autotetraploid population with arbitrary rate of partial selfing and double reduction. The resulted formula, and numerical study based on the formula, indicated that the effective size decreases by the increase of probability of double reduction and the rate of selfing. When there is complete selfing, however, the effective size is not affected by the probability of double reduction.

scholarly journals Effective size of nonrandom mating populations.

Genetics ◽  
1992 ◽  
Vol 130 (4) ◽  
pp. 909-916 ◽  
Author(s):  
A Caballero ◽  
W G Hill
Keyword(s):  
Population Size ◽  
Effective Population Size ◽  
Family Size ◽  
Genetic Drift ◽  
Effective Size ◽  
Effective Population ◽  
Gene Frequencies ◽  
Nonrandom Mating ◽  
Sib Mating ◽  
Census Number

Abstract Nonrandom mating whereby parents are related is expected to cause a reduction in effective population size because their gene frequencies are correlated and this will increase the genetic drift. The published equation for the variance effective size, Ne, which includes the possibility of nonrandom mating, does not take into account such a correlation, however. Further, previous equations to predict effective sizes in populations with partial sib mating are shown to be different, but also incorrect. In this paper, a corrected form of these equations is derived and checked by stochastic simulation. For the case of stable census number, N, and equal progeny distributions for each sex, the equation is [formula: see text], where Sk2 is the variance of family size and alpha is the departure from Hardy-Weinberg proportions. For a Poisson distribution of family size (Sk2 = 2), it reduces to Ne = N/(1 + alpha), as when inbreeding is due to selfing. When nonrandom mating occurs because there is a specified system of partial inbreeding every generation, alpha can be substituted by Wright's FIS statistic, to give the effective size as a function of the proportion of inbred mates.

scholarly journals Effective population size for culturally evolving traits

2021 ◽  
Author(s):  
Dominik Deffner ◽  
Anne Kandler ◽  
Laurel Fogarty
Keyword(s):  
Population Genetics ◽  
Social Network ◽  
Cultural Diversity ◽  
Population Size ◽  
Effective Population Size ◽  
Network Structure ◽  
Cultural Exchange ◽  
Effective Size ◽  
Effective Population ◽  
Social Network Structure

ABSTRACTPopulation size has long been considered an important driver of cultural diversity and complexity. Results from population genetics, however, demonstrate that in populations with complex demographic structure or mode of inheritance, it is not the census population size, N, but the effective size of a population, Ne, that determines important evolutionary parameters. Here, we examine the concept of effective population size for traits that evolve culturally, through processes of innovation and social learning. We use mathematical and computational modeling approaches to investigate how cultural Ne and levels of diversity depend on (1) the way traits are learned, (2) population connectedness, and (3) social network structure. We show that one-to-many and frequency-dependent transmission can temporally or permanently lower effective population size compared to census numbers. We caution that migration and cultural exchange can have counter-intuitive effects on Ne. Network density in random networks leaves Ne unchanged, scale-free networks tend to decrease and small-world networks tend to increase Ne compared to census numbers. For one-to-many transmission and different network structures, effective size and cultural diversity are closely associated. For connectedness, however, even small amounts of migration and cultural exchange result in high diversity independently of Ne. Our results highlight the importance of carefully defining effective population size for cultural systems and show that inferring Ne requires detailed knowledge about underlying cultural and demographic processes.AUTHOR SUMMARYHuman populations show immense cultural diversity and researchers have regarded population size as an important driver of cultural variation and complexity. Our approach is based on cultural evolutionary theory which applies ideas about evolution to understand how cultural traits change over time. We employ insights from population genetics about the “effective” size of a population (i.e. the size that matters for important evolutionary outcomes) to understand how and when larger populations can be expected to be more culturally diverse. Specifically, we provide a formal derivation for cultural effective population size and use mathematical and computational models to study how effective size and cultural diversity depend on (1) the way culture is transmitted, (2) levels of migration and cultural exchange, as well as (3) social network structure. Our results highlight the importance of effective sizes for cultural evolution and provide heuristics for empirical researchers to decide when census numbers could be used as proxies for the theoretically relevant effective numbers and when they should not.

Effective size closely approximates the census size in the heavily exploited western Atlantic population of the sandbar shark, Carcharhinus plumbeus

2008 ◽  
Vol 10 (6) ◽  
pp. 1697-1705 ◽  
Author(s):  
David S. Portnoy ◽  
Jan R. McDowell ◽  
Camilla T. McCandless ◽  
John A. Musick ◽  
John E. Graves
Keyword(s):  
Effective Size ◽  
Sandbar Shark ◽  
Carcharhinus Plumbeus ◽  
Western Atlantic ◽  
Atlantic Population ◽  
Census Size

scholarly journals Values of Selected Biochemical and Mineral Metabolism Indicators in Feathered Game

2010 ◽  
Vol 79 (9) ◽  
pp. S9-S12 ◽  
Author(s):  
Pavel Suchý ◽  
Eva Straková ◽  
Leo Kroupa ◽  
Ladislav Steinhauser ◽  
Ivan Herzig
Keyword(s):  
Broiler Chickens ◽  
Current Knowledge ◽  
Mineral Metabolism ◽  
Meleagris Gallopavo ◽  
Individual Species ◽  
Wild Turkey ◽  
Mean Values ◽  
Grey Partridge ◽  
Interspecies Differences ◽  
Physiological Range

The present paper extends the current knowledge of biochemical and mineral profiles in selected species of feathered game such as helmeted guineafowl (Numida meleagris), common pheasant (Phasianus colchicus), Japanese quail (Coturnix coturnix japonica), chukar (Alectoris chucar), grey partridge (Perdix perdix) and wild turkey (Meleagris gallopavo) reared in the Czech Republic and throughout Europe. The work evaluates potential interspecies differences among the values and compares the findings with the results reported for related domesticated species of birds. Indicators investigated in the individual species of feathered game such as total protein (TP), glucose (GLU), total cholesterol (CHOL), triacylglycerides (TAG), uric acid (UA), alanine aminotransferase (ALT) and Ca, P, Mg, Na, K, Cl varied in ranges typical for layers and broiler chickens. Except for wild turkey where mineral metabolism values reached or even exceeded the upper limit of the physiological range, which may indicate a specific interspecies difference. However, with regard to the wide physiological range of biochemical indicators in the blood of birds, significant (P ⪬ 0.05) and highly significant (P ⪬ 0.01) differences in most mean values for the monitored indicators can not be evaluated as interspecies differences.

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