Heredity 

About: Heredity is an academic journal published by Nature Portfolio. The journal publishes majorly in the area(s): Population & Genetic variation. It has an ISSN identifier of 0018-067X. Over the lifetime, 7351 publications have been published receiving 343995 citations. The journal is also known as: inheritance.

Intra-sexual selection in Drosophila.

Abstract: SINCE Darwin first wrote on the subject in 1871, sexual selection has been generally accepted as one of the basic facts of biology. The evidence in its favour seems, however, to be mainly circumstantial. Its existence has usually been inferred from sex differences depending on what are called secondary sexual characters which are supposed to have arisen as results of that selection. Such an approach has its dangers, and Huxley (1938) has made important criticisms of the original concept of sexual selection. He has shown that a large number of characters which have been attributed to sexual selection are unconnected with competition for mates. This is particularly the case in monogamous birds which offer some of the most striking examples of secondary sexual differences. In the first place monogamy, at least when the sexes are numerically equal, is the mating system least likely to develop sexual selection. In the second place, and more important, observations on bird behaviour have shown that much of the display of birds occurs after pairing, when competition must have ceased. Such sexual differences are concerned, either with inducing the female to copulate, or with maintaining the association of the sexes as long as it is necessary for the rearing of the young. Huxley therefore introduced the term epigamic to apply to characters which increased the fertility of a given mating and therefore had a selective value for the species as a whole. Epigamic selection includes the major part of what Darwin meant by sexual selection. It also includes selection for characters to which Darwin did not refer, such as the structure of copulatory organs, sex differences in frequency of crossing over, and the XY mechanism. It is only a special case of natural selection as generally understood. What remains of Darwinian sexual selection has been called intra-sexual selection, which denotes that it involves competition between members of one sex for mates. It can only indirectly affect the survival of the species and then is often deleterious (e.g. the cumbersome antlers of the stag). There is not invariably, however, a clear distinction between epigamic and intrasexual selection. In a promiscuous species like Drosophila pairing and copulation are synchronous. Courtship behaviour determines the number of mates and therefore enters into intra-sexual selection.

The Ecology of Adaptive Radiation

Abstract: This volume is the ®rst of three volumes from a Festschrift marking the occasion of Richard C. Lewontin's 65th birthday and the approximate time of his retirement. The volumes were planned and invitations to authors were formalized in 1996. This ®rst volume appeared in 2000, but a celebration, colloquially referred to as Dickfest, was held on September 6, 1998 at the Museum of Comparative Zoology at Harvard. The frontispiece is a photograph of 115 friends, former students and post docs that attended Dickfest. Dick Lewontin has been a leader in population genetics and evolution for over 40 years, and his in ̄uence has been enhanced by interactions with more than 100 graduate students and postdocs. He is most widely known for the innovation of using electrophoretic surveys of proteins to quantify genetic variation within and among populations. This innovation triggered thousands of studies of plant, animal, and microbial populations, providing the data that inspired the neutral theory and fuelled the festering debate between neutralists and selectionists. Lewontin also made numerous theoretical contributions, most notably on linkage disequilibrium and units of selection. The book contains 32 chapters organized into eight sections: historical perspectives on population genetics; molecular evolution; selection, linkage and breeding systems; quantitative genetics; gene ̄ow and population structure; population genetics and speciation; and behavioural ecology. Each section begins with a preface that provides historical perspective and organizational overview. The book has a subject index and a listing of Lewontin's publications, currently 274 and still growing. I wish they had included a diagram of his academic genealogy. Because the 32 chapters are grouped into eight sections, the coverage of any section is sketchy and partially dependent on the historical contingency of the author being associated with Lewontin. This Festschrift will be valued as an historic marker, the celebration, hosted by his academic family, of an accomplished scientist, rather than as a focused academic e€ort. Nevertheless, this volume contains some ®ne papers. The ®rst chapter, by Dick Lewontin, entitled `The Problems of Population Genetics', is a familiar theme that Lewontin treats with authority. Parts of the chapter are echoes of earlier reviews, a litany of what we do not know and cannot know. Some of this is unjusti®ed pessimism commonly mistaken for scienti®c rigor. Other parts, such as his discussions of codon bias and comparisons of coding and noncoding sites, are novel and uncharacteristically optimistic. Several chapters were particularly noteworthy. Bruce Wallace provided an historic analysis of heterosis, pointing out that `neutrality of phenotypic variation arises as an average of many, non-neutral selective roles played by individual variants during decisive encounters'. Andrew Berry and Antonio Barbadilla showed that, while recombination is most important for exchanging fragments between loci, gene conversion is much more important for generating diversity within a locus. Eleftherios Zouros and David Rand provided a thoughtful, comprehensive overview of the evolutionary forces in ̄uencing the evolution of mtDNA, and the implications of various forms of selection for phylogeographic studies. Jerry Coyne and Allen Orr summarized recent progress on the genetics of speciation. The second volume from Dickfest appeared in 2001, and the third is in preparation.

A simple regression method for mapping quantitative trait loci in line crosses using flanking markers.

Abstract: The use of flanking marker methods has proved to be a powerful tool for the mapping of quantitative trait loci (QTL) in the segregating generations derived from crosses between inbred lines. Methods to analyse these data, based on maximum-likelihood, have been developed and provide good estimates of QTL effects in some situations. Maximum-likelihood methods are, however, relatively complex and can be computationally slow. In this paper we develop methods for mapping QTL based on multiple regression which can be applied using any general statistical package. We use the example of mapping in an F(2) population and show that these regression methods produce very similar results to those obtained using maximum likelihood. The relative simplicity of the regression methods means that models with more than a single QTL can be explored and we give examples of two lined loci and of two interacting loci. Other models, for example with more than two QTL, with environmental fixed effects, with between family variance or for threshold traits, could be fitted in a similar way. The ease, speed of application and generality of regression methods for flanking marker analysis, and the good estimates they obtain, suggest that they should provide the method of choice for the analysis of QTL mapping data from inbred line crosses.

Natural selection and the heritability of fitness components

Abstract: The hypothesis that traits closely associated with fitness will generally possess lower heritabilities than traits more loosely connected with fitness is tested using 1120 narrow sense heritability estimates for wild, outbred animal populations, collected from the published record. Our results indicate that life history traits generally possess lower heritabilities than morphological traits, and that the means, medians, and cumulative frequency distributions of behavioural and physiological traits are intermediate between life history and morphological traits. These findings are consistent with popular interpretations of Fisher's (1930, 1958) Fundamental Theorem of Natural Selection, and Falconer (1960, 1981), but also indicate that high heritabilities are maintained within natural populations even for traits believed to be under strong selection. It is also found that the heritability of morphological traits is significantly lower for ectotherms than it is for endotherms which may in part be a result of the strong correlation between life history and body size for many ectotherms.

Indirect measures of gene flow and migration: FST≠1/(4Nm+1)

Abstract: The difficulty of directly measuring gene flow has lead to the common use of indirect measures extrapolated from genetic frequency data. These measures are variants of FST, a standardized measure of the genetic variance among populations, and are used to solve for Nm, the number of migrants successfully entering a population per generation. Unfortunately, the mathematical model underlying this translation makes many biologically unrealistic assumptions; real populations are very likely to violate these assumptions, such that there is often limited quantitative information to be gained about dispersal from using gene frequency data. While studies of genetic structure per se are often worthwhile, and FST is an excellent measure of the extent of this population structure, it is rare that FST can be translated into an accurate estimate of Nm.