Sex determination in mythology and history.
The history of ideas on how the sexes became divided spans at least three thousand years. The biblical account of the origin of Eve, and the opinions of the philosophers of classical Greece, have unexpected bearings on present-day ideas. The scientific study of sex determination can be said to have begun in the 17th century with the discovery of spermatozoa, but the origin and function of the "spermatic animalcules" eluded investigators until 1841. The mammalian egg was discovered in 1827, and in the last quarter of the century fertilization was observed. The view current at that time, that sex determination was under environmental control, gave way to the idea of chromosomal determination in the first quarter of the 20th century. The study of human and other mammalian chromosomes during the third quarter of the century, and the discovery of sex-chromosome abnormalities, emphasized the importance of the Y chromosome for male sex determination. The last quarter of the century witnessed a hunt for the "testis-determining" gene, thought to be responsible for the differentiation of Sertoli cells, and culminating in the isolation of SRY (Sry in the mouse). However, an increasing number of additional genes and growth factors were found to be required for the establishment of male sex. During the same period evidence emerged that male development was accompanied by enhanced growth, both of gonads and whole embryos. An unexpected finding was the demonstration of temperature-dependent sex determination in reptiles. With the advent of the 21st century, it was shown that Sry induces cell proliferation in fetal mouse gonads, and it has been suggested that male sex differentiation in mammals requires a higher metabolic rate. These insights could lead to a better understanding and improved treatment of abnormalities of sexual development.
Department of Biology, University College London, UK. u.mittwoch@ucl.ac.uk
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Mittwoch
D005260:Female; D006664:History; D006801:Humans; D008297:Male; D009229:Mythology; D019849:Sex Determination Processes