| Popis: |
ALTHOUGH the heterogamety of the female for sex in the fowl has been known since 1908 (Spillman, 1908), the chromosomal mechanism for its determination was not ascertained to the satisfaction of most cytologists until 1930 (Suzuki, 1930), and there are still several reservations in the minds of some as to the complete adequacy of the identification on genetic grounds (Newcomer & Brant, 1954) (Newcomer, 1957, 1959a). At the present time and with existing techniques, it seems clear that the two sexes differ at least by the possession of the female of one small metacentric chromosome whereas the male carries two. Sex reversal in the fowl has been achieved by artificial means (Domm, 1939), and it occasionally occurs naturally. The former is usually accomplished by ovariotomy and the latter has been most often, but not always (Carne & Waterhouse, 1958), associated with a pathological condition of the ovary or a general … |
