Summary
The wood lemming, Myopus schisticolor, possesses a unique sex determining system comprising both XX and XY females. Normal female development in the presence of XY is guaranteed by a mutation on the X, apparently associated with a structural rearrangement in Xp. This mutation inactivates the testis-inducing and male-determining factor on the Y and distinguishes X* from X, and X*Y females from XY males. Normal fertility of X*Y females is ensured by a mitotic (double) nondisjunction mechanism which, at an early fetal stage, eliminates the Y from the germ line and replaces it by a copy of the X*.
Numerical sex chromosome aberrations are not infrequent and the trisomics XXY and X*XY are relatively common. XXY individuals are sterile males with severe suppression of spermatogenesis. Among X*XY animals, both males and females, as well as a true lateral hermaphrodite have been observed. Primary deficiency of germ cells, impairment of spermatogenesis and sterility are characteristic traits of the X*XY males, whereas X*XY females have normal oogenesis and are fertile. Both these extremes (except female fertility) coexist in the true hermaphrodite described in the present study. These apparently contradictory observations are explainable under the assumption that X* and X in X*XY individuals are inactivated non-randomly or that the cells are distributed unequally. Inactivation of the X or X* determines whether or not the H-Y antigen will be expressed. When comparing conditions in Myopus and in man, an additional assumption has to be made in relation to the gene(s) involved in sex determination, located in Xp:In Myopus they do not escape inactivation, whereas in man they have been claimed to remain active.
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References
Cattanach BM (1974) Genetic disorders of sex determination in mice and other mammals. In: Motulsky AG, Lenz W (eds) Proc 4th Int Conf, Vienna, Austria, 2nd–8th Sept 1973. Excerpta Medica, Amsterdam, pp 129–141
Eicher EM, Beamer WG, Washburn LL, Whitten WK (1980) A cytogenetic investigation of inherited true hermaphroditism in BALB/cWt mice. Cytogenet Cell Genet 28:104–115
Evans EP, Burtenshaw MD, Ford CE (1972) Chromosomes of newborn young: Preparations from membranes and tail tips. Stain Technol 47:229–234
Fredga K, Gropp A, Winking H, Frank F (1976) Fertile XX-and XY-type females in the wood lemming Myopus schisticolor. Nature (Lond) 261:225–227
Fredga K, Gropp A, Winking H, Frank F (1977) A hypothesis explaining the exceptional sex ratio in the wood lemming (Myopus schisticolor). Hereditas (Lund) 85:101–104
Gropp A, Winking H, Frank F, Noack G, Fredga K (1976) Sexchromosome aberrations in wood lemmings (Myopus schisticolor). Cytogenet Cell Genet 17:343–358
Herbst EW, Fredga K, Frank F, Winking H, Gropp A (1978) Cytological identification of two X-chromosome types in the wood lemming (Myopus schisticolor). Chromosoma 69:185–191
Ohno S, Wachtel SS, Koo GC (1976) Hormone-like role of H-Y antigen in bovine Freemartin gonad. Nature 261:587–599
Seabright M (1971) A rapid banding technique for human chromosomes. Lancet II:971–972
Sumner AT (1972) A simple technique for demonstrating centromeric heterochromatin. Exp Cell Res 75:304–306
Wachtel SS, Hall JL, Müller U, Chaganti RSK (1980) Serum-borne H-Y antigen in the fetal bovine Freemartin. Cell 21:917–926
Wachtel SS, Koo GC, Ohno S (1977) H-Y antigen and male development. In: Troen P, Nankin HR (eds) The testis in normal and infertile men. Raven Press, New York, pp 35–43
Wachtel SS, Koo GC, Ohno S, Gropp A, Dev VG, Tantravahi R, Miller DA, Miller OJ (1976) H-Y antigen and the origin of XY female wood lemmings (Myopus schisticolor). Nature (Lond) 264:638–639
Winters SJ, Wachtel SS, White BJ, Koo GC, Javadpour N, Loriaux L, Sherins RJ (1979) H-Y antigen mosaicism in the gonad of a 46,XX true hermaphrodite. N Engl J Med 300:745–749
Wolf U, Fraccaro M, Mayerová A, Hecht T, Maraschio P, Hameister H (1980) A gene controlling H-Y antigen on the X chromosome. Hum Genet 54:149–154
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Winking, H., Gropp, A. & Fredga, K. Sex determination and phenotype in wood lemmings with XXY and related karyotypic anomalies. Hum Genet 58, 98–104 (1981). https://doi.org/10.1007/BF00284156
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DOI: https://doi.org/10.1007/BF00284156