| 释义 |
lyonization, n. Genetics.|ˌlaɪənaɪˈzeɪʃən|
Also Lyonization.
[f. the name of Mary Frances Lyon (b. 1925), English biologist, who proposed the idea (Nature (1961) 22 Apr. 372/1).]
A process occurring in the very early stages of development of female mammalian embryos, in which one of the two X chromosomes is randomly inactivated in each of the existing cells.
1963Lancet 12 Oct. 769/1 Mary Lyon proposed her hypothesis..in 1961... A colloquium on chromosome anomalies and D.N.A., held in Oporto on Sept. 12–14, devoted a good part of its time to this subject... This ‘Lyonisation’ (a convenient word invented at the colloquium) occurs in man presumably about the 12th day. 1977Lancet 13 Aug. 339/2 This first occurs early in the growth of the female embryo, when a random decision on which chromosome to inactivate is apparently taken by each of the small number of cells then present, setting a precedent which is thereafter faithfully followed in each cell line, a process known as lyonisation. 1987C. A. Clarke Human Genetics & Med. (ed. 3) viii. 59 Lyonization..explains why 15{pcnt} of carrier females of the haemophilia gene have a normal concentration of factor VIII. |
