The origin of male haploid genetic systems and their expected sex ratio
TL;DR: These calculations show that male haploidy can evolve in a single, panmictic, diplodiploid population by a process which is not very different from the replacement of one gene by another.
About: This article is published in Theoretical Population Biology.The article was published on 1970-08-01. It has received 103 citations till now. The article focuses on the topics: Arrhenotoky & Haplodiploidy.
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TL;DR: It is the view that a whole series of factors acting jointly or alternately is responsible for the numerous origins of sociality in Hymenoptera, compared to only one in all the other insects.
Abstract: Kin selection has been used to explain evolution of man altruistic traits found in those social insect castes which have reduced reproductivity. Kin selection is most probable among organisms living in family groups. It is commonly assumed, therefore, that (1) the most primitive social insects, like the more specialized ones, live in mother-daughter (eusocial) colonies, (2) colonies of individuals of the same generation and showing castes (semisocial colonies) are abnormal or originate only in inbreeding populations, and (3) transfer of individuals among colonies must be selected against, except in inbreeding populations. Numerous Hymenoptera are cited, however, in which semisociality or transfer occurs in populations lacking evidence for inbreeding; and we believe that, in explaining the origin of social behavior in insects, Hamilton and others have placed too much emphasis on the evolution of altrustic behavior through kin selection. There is considerable evidence that social behavior in insects is in p...
403 citations
TL;DR: The haploid males and diploid females of Hymenoptera have all chromosomes in the same proportions, which rules out most familiar sex-determining mechanisms, which rely on dosage differences at sex determination loci.
Abstract: The haploid males and diploid females of Hymenoptera have all chromosomes in the same proportions. This rules out most familiar sex-determining mechanisms, which rely on dosage differences at sex determination loci. Two types of model — genie balance and complementary sex determination (CSD) — have been invoked for Hymenoptera. Experimental studies provide no good evidence for genie balance models, which are contradicted by the detection of diploid males in 33 disparate species. Furthermore, recent advances have shown that sex determination in the best-studied diploid animals does not depend on genie balance, removing the original justification for hymenopteran genie balance models. Instead, several Hymenoptera have single-locus CSD. In this system, sex locus heterozyotes are female while homozygotes and hemizygotes are male. Single-locus CSD does not apply to several inbreeding species and this probably reflects selection against the regular production of diploid males, which are sterile. A multilocus CSD model, in which heterozygosity at any one of several sex loci leads to female development has also been proposed. To date, multilocus CSD has not been demonstrated but several biases against its detection must be considered. CSD can apply to thelytokous races as long as the cytogenetic mechanism permits retention of sex locus heterozygosity. However, some thelytokous races clearly do not have CSD. The distribution of species with and without CSD suggests that this form of sex determination may be ancestral in the Hymenoptera. However, phylogenetic analyses are hindered by the lack of data from several superfamilies and the fact that the internal phylogeny of the Hymenoptera remains controversial.
395 citations
TL;DR: Sex determination in the model hymenopteran Nasonia vitripennis does not involve CSD, but it is consistent with a form of genomic imprinting in which activation of the female developmental pathway requires paternally derived genes.
Abstract: The dominant and ancestral mode of sex determination in the Hymenoptera is arrhenotokous parthenogenesis, in which diploid females develop from fertilized eggs and haploid males develop from unfertilized eggs. We discuss recent progress in the understanding of the genetic and cytoplasmic mechanisms that make arrhenotoky possible. The best-understood mode of sex determination in the Hymenoptera is complementary sex determination (CSD), in which diploid males are produced under conditions of inbreeding. The gene mediating CSD has recently been cloned in the honey bee and has been named the complementary sex determiner. However, CSD is only known from 4 of 21 hymenopteran superfamilies, with some taxa showing clear evidence of the absence of CSD. Sex determination in the model hymenopteran Nasonia vitripennis does not involve CSD, but it is consistent with a form of genomic imprinting in which activation of the female developmental pathway requires paternally derived genes. Some other hymenopterans are not arrhenotokous but instead exhibit thelytoky or paternal genome elimination.
394 citations
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TL;DR: A genetical mathematical model is described which allows for interactions between relatives on one another's fitness and a quantity is found which incorporates the maximizing property of Darwinian fitness, named “inclusive fitness”.
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