Testis-determining H-Y antigen in XO males of the mole-vole (Ellobius lutescens)

Data on fauna of gamasina mites parasitizing on small mammals are provided in article. Data are obtained during long-term monitoring of an ecological complex of small mammals of a natural and territorial complex Samarskaya Luka, which is realized since 1999. Also data on fauna of gamasina mites in 14 years of researches (2000-2003, 2005, 2007-2015 years), including literary data about the gamasina mites of this territory, are generalized and analysed. Specific accessory of 7439 individuals of mites, seven childbirth of three families relating to fifteen types is defined. Parasitizing the gamasina mites on 16 species of small mammals, including groups rodents, soricomorpha, carnivora (least weasel) is established. Domination of separate species of mites is revealed, so to eudominant Laelaps hilaris and Hirstionyssus isabellinus are belong, dominants are - Hirstionyssus ellobii , Haemolaelaps glasgowi , Hyperlaelaps arvalis , L. agilis . Myonyssus rossicus , L. algericus , Haemogamasus ambulans and Hirstionyssus macedonicus were extremely rare species met in single copies. For the first time for this territory types of H. ellobii , L. micromydis , H. ambulans , H. macedonicus are noted. Conclusions on degree of a confinedness of parasites to certain types of hosts are drawn. Monohostal types: L. agilis (the host - a yellow-necked mouse), L. muris (the host - a tundra vole and a water vole), L. micromydis (the host - a small mouse), L. algericus (the host - a house mouse), H. arvalis (the host - a tundra vole and a water vole), H. ellobii (the host - a northern mole vole). Polihostal: H. musculi , L. hilaris , H. isabellinus , H. glasgowi , E. stabularis , H. nidi .

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From brain determination to testis determination: evolution of the mammalian sex-determining gene

Reproduction Fertility and Development ◽

10.1071/rd01093 ◽

2001 ◽

Vol 13 (8) ◽

pp. 665 ◽

Cited By ~ 20

Author(s):

Jennifer A. Marshall Graves

Keyword(s):

Y Chromosome ◽

Sex Chromosome ◽

Critical Role ◽

Dominant Gene ◽

Comparative Gene Mapping ◽

Good Account ◽

Mole Vole ◽

Sex Chromosome System ◽

Testis Determination ◽

Autosome Pair

In mammals, sex is determined by an XY male:XX female sex chromosome system in which a male-dominant gene on the Y chromosome (SRY) determines testis formation. Sex chromosomes evolved from an ordinary autosome pair as the Y chromosome was progressively degraded. The Y chromosome has lost nearly all of its 1500 original genes, and those that survived did so because they evolved a critical role in male determination or differentiation. SRY is typical of Y-borne genes. Comparative gene mapping and sequencing shows that SRY arose quite recently as a degraded version of the SOX3 gene on the X chromosome. SOX3 is expressed predominantly in brain, and so is more likely to be a brain-determining than a testis-determining gene. The male-dominant action of SRY may be an illusion, as its structure suggests that it works by interfering with the action of a related gene, which in turn inhibits testis development. This hypothesis can give a good account of how a brain-determining gene acquired a role in testis determination via differential dosage of SOX3. SRY has no central role in sex determination and it can be replaced as a trigger and lost, as have many other Y-borne genes in recent evolutionary history. The absence of SRY in two species of the mole vole (Ellobius) suggests that its useful life is already running out.

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