Extraordinary multilocus genetic organization in mole crickets, gryllotalpidae

Eviatar Nevo, Avigdor Beiles, Abraham B. Korol, Yefim I. Ronin, Tomas Pavlicek, William Hamilton

Research output: Contribution to journalArticlepeer-review

Abstract

Allozymic diversity at 21 loci was analyzed in 470 individuals of three species of mole cricket superspecies, Gryllotalpa gryllotalpa (two new chromosomal species, G. tali and G. marismortui) and G. africana in Israel, which are distributed along a southward transect of increasing aridity. Two outstanding findings emerged in G. tali and G. marismortui: (1) genetic polymorphism was high but heterozygosity very low, indicating significant deviations from Hardy-Weinberg expectations; and (2) significant linkage disequilibria at an unprecedented level for outbreeders and remarkable intersite differences. The results may characterize subterranean gryllotalpids worldwide because a single sample of Neocurtilla hexadactyla from Tefe, Amazonia, shows the same features. Significant variation of heterozygote paucity among loci, combined with the biology of the species, rejects the simple explanation of inbreeding or any other single explanatory model. Likewise, direct selection against heterozygotes or specific multilocus associations can explain, but is not necessary nor likely to explain, the observed results in mole crickets. To explain these results, we developed a multiple-factor mathematical model combining niche viability selection, niche choice, and positive assortative mating. This model involves a special case of Wahlund effect and inbreeding. Simulations based on this model showed that a combination of these three mechanisms may produce the observed distribution of alleles, via selection on a few loci, to affect the entire genome organization.

Original languageEnglish
Pages (from-to)586-605
Number of pages20
JournalEvolution
Volume54
Issue number2
DOIs
StatePublished - Apr 2000

Keywords

  • Habitat choice
  • Hardy-Weinberg equilibrium
  • Heterozygosity
  • Linkage disequilibrium
  • Mate choice
  • Polymorphism
  • Selection

ASJC Scopus subject areas

  • General Agricultural and Biological Sciences
  • Genetics
  • Ecology, Evolution, Behavior and Systematics

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