Sex differentiation and development : proceedings of a symposium held at the Royal Scoiety of Medicine, Wimpole Street, London, on 10 and 11 April 1958 / edited on behalf of the Society for Endocrinology by C.R. Austin.

  • Symposium on Sex Differentiation and Development (1958 : London, England)
Date:
1960
Catalogue details

Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: Sex differentiation and development : proceedings of a symposium held at the Royal Scoiety of Medicine, Wimpole Street, London, on 10 and 11 April 1958 / edited on behalf of the Society for Endocrinology by C.R. Austin. Source: Wellcome Collection.

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    SEX DETERMINATION AND GASTE DIFFERENTIATION IN THE HONEYBEE (APIS MELLIFERA) By С. G. BUTLER Over 100 years ago, Dzierzon [1845] stated his well-known theory that unfertilized eggs of the honeybee always give rise to males—drones—whereas fertilized eggs always give rise to females, which may become either workers or queens, depending upon the manner in which the larvae concerned are fed by the worker members of their colony. Dzierzon suggested that a normal, mated queen can lay either a fertilized or an un¬ fertilized egg at wiU, and that the kind of egg she lays depends on the kind of cell— worker, queen or drone—in which she is about to lay. The Dzierzon theory has, of course, become well established, although it is now known that females can sometimes develop from unfertilized honeybee eggs. In fact, in two races of honeybees, the South African Cape bee [Apis mellifera capensis) and the Tunisian bee [A. mellifera intermissa), it has been reported that both queens and workers are frequently reared from unfertiHzed eggs [Jack, 1916; Gough, 1928]. An American worker, Mackensen [1943], has also demonstrated that such impatemate females occasionally occur in several races of European honeybees, and he succeeded in rearing queens as well as workers from such unfertilized eggs. The mechanism by which such impatemate females are produced in the honeybee is unknown, but Ruttner & Mackensen [1952] have suggested that perhaps the mechanism is similar to that which is beHeved to occur in the parasitic wasp Habrobracon, in which Speicher &c Speicher [1938] have obtained cytological evidence indicating that they probably arise from tetraploid tissue in the ovaries. Perhaps the Cape and Tunisian honeybees tend to have such tissue in their ovaries and, as a result of reduction, the egg becomes diploid and consequently develops into a female without fertilization. According to Nachtsheim [1913], and various other workers, the honeybee sperm has sixteen chromosomes and the fertilized egg thirty-two. Two theories of sex determination in the honeybee have been put forward. In the first. Manning [1949-50] has claimed that sex determination is dependent upon the presence of a sex chromosome that is lost in the development of the sperm. According to his theory, both male and female possess only a single sex chromosome, although the female has twice as many autosomes as the male. He supposes that, during the formation of the ovum, differential maturation results in the sex chromosome always remaining in the nucleus of the ovum, with the result that a mature ovum contains fifteen autosomes together with a single sex chromosome and, if unfertilized, gives rise to a male. On the other hand, fertilized eggs contain thirty autosomes and a sex chromosome and develop into females. However, Sanderson & Hall [1951] have sub¬ sequently confirmed their previous finding of sixteen chromosomes in the male and The Editor accepts no responsibility Jar the accounts oj the papers read at the Symposium. Manuscripts are published as received from the authors. 3
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