Sex-lethal, a link between sex determination and sexual differentiation in Drosophila melanogaster.
Sex-lethal, a link between sex determination and sexual differentiation in Drosophila melanogaster.
复制标题
性致死，果蝇性别决定和性别分化之间的联系。
DOI：
10.1101/sqb.1985.050.01.072
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发表时间：
1985
期刊：
影响因子：
--
通讯作者：
T. Cline
中科院分区：
文献类型：
--
作者：
E. M. Maine;H. Salz;P. Schedl;T. Cline
Early in this century it was discovered that a rather small change (50O7o) in the relative number of X chromosomes in Drosophila melanogaster is responsible for one of the more striking examples of differential gene expression observed in higher eukaryotes. This classical illustration of a fundamental puzzle in developmental biology involves fruit fly sexual differentiation. Diploid cells with two X chromosomes (X chromosomes: sets of autosomes= 1) differentiate as female, whereas diploid cells with only one X chromosome (X: A= 0.5) differentiate as male (Bridges 1925). Since that time, considerable progress has been made toward understanding the nature of this quantitative developmental signal and the mechanism by which it is transduced into the remarkable qualitative and quantitative differences in development between the sexes (for review, see Baker and Belote 1983; Cline 1985). Recent experimental evidence suggests that although cells carry their sex-determination signal (the X: A balance) with them throughout development, they seem to read this signal only early in development, long before most overt aspects of sexual differentiation occur. They then initiate a sexual pathway commitment that seems to be maintained independent of the initiating signal (Cline 1985 and unpubl.). Thus, for Drosophila, the term sex determination seems to apply not only in its general sense, but also in the much more restricted sense of developmental pathway commitments maintained epigenetically by dividing cells. The classical paradigm for" determination" in this latter sense involves the process by which the precursor cells of the adult Drosophila integument acquire and maintain their segmental and subsegmental identities (Gehring 1972). Comparisons between the mechanisms of sex determination and segmental determination of Drosophila may lead to the discovery of common molecular mechanisms that govern developmental pathway commitments in metazoans.Three broad aspects of Drosophila sexual development can be considered: initiation of the sexual pathway commitment, maintenance of the pathway commitment, and expression of the pathway commitment. We discuss here some of the ways that one can distinguish among genetic perturbations that disrupt different steps in this process, even when different perturbations involve the same gene. Awareness of these distinctions is likely to be important for understanding the way regulatory genes coordinate multicellular development.
