Thelytoky
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Thelytoky is the reproduction of female workers or queens by laying worker bees. Thelytoky occurs in the Cape bee, Apis mellifera capensis and has been found in other strains at very low frequency.
Usually, unfertilized eggs are haploid containing only a single set of chromosomes (16) from the mother. Cape bee laying workers are capable of laying unfertilized diploid (32 chromosomes) eggs. These eggs undergo an unusual biological life cycle. One stage during meiosis is anaphase when the chromosomes separate. In parthenogenesis (the reproduction without male fertilization), anaphase is followed by fusion of two meiotic products to restore egg diploidy (the egg pronucleus and the central descendant of the first polar body fuse to form a diploid nucleus called zygote).
Depending on how the zygote (diploid egg) is fed it can develop into a worker bee or a queen bee.
Thelytoky can also refer to any obligatory parthenogenesis in other organisms.
Thelytoky is a type of parthenogenesis in which females are produced from unfertilized eggs. It is common in invertebrates, like arthropods, but can also occur in vertebrates, like some whiptail lizards. It can occur by a number of different mechanisms. Bees and other Hymenoptera are haplodiploid and usually reproduce by arrhenotokous parthenogenesis, in which unfertilized eggs develop into haploid males, and fertilized eggs develop into diploid females. However, thelytokous parthenogenesis is common and can be induced by the bacteria Wolbachia and Cardinium [1]. Thelytoky occurs in the Cape bee, Apis mellifera capensis and has been found in other strains at very low frequency. In honeybees, thelytoky occurs when diploidy is restored by the fusion of two meiotic products[2].
[edit] References
- ^ G. Jeong and Stouthamer, R. (2005) Genetics of female functional virginity in the Parthenogenesis-Wolbachia infected parasitoid wasp Telenomus nawai (Hymenoptera: Scelionidae). Heredity 94:402-407
- ^ E. Baudry et al. (2004) Whole-Genome Scan in Thelytokous-Laying Workers of the Cape Honeybee (Apis mellifera capensis): Central Fusion, Reduced Recombination Rates and Centromere Mapping Using Half-Tetrad Analysis. Genetics 167:243-252
