| 释义 |
epistasis|ɛˈpɪstəsɪs|
[Gr. ἐπίστασις a stopping, stoppage, (also) scum on urine, f. ἐϕιστάναι to stop, check.]
1. Med.
a. The checking of any discharge, as of blood or menses.
b. A pellicle that forms on the surface of urine after it has stood. rare—0
[1849F. Adams Genuine Wks. Hippocrates II. Aphorisms vii. no. 35 When the scum on the surface is fatty and copious, it indicates acute diseases of the kidneys. [Note] It appears from Galen, that in some copies he found epistasis, and in others hypostasis; the one evidently referring to the scum on the surface, and the latter to the sediment: he favours the former reading, and understands it to refer to melting of the fat in the neighbourhood of the kidneys. ]
1807Morris & Kendrick Edin. Med. & Physical Dict. II. Gloss., Epistasis, see Epischesis [= ‘a suppression of excretions’]. Also the substance on the surface of the urine. 1848in Dunglison. 1889in Cent. Dict. 1934in Webster; and in mod. med. dicts.
2. Genetics. [Back-formation from epistatic a.] The expression of one hereditary character to the exclusion of another when the two are controlled by alleles of different genes; also more widely, any interaction of non-allelic genes.
1917Genetics II. 613 (index) Epistasis. 1932Sinnot & Dunn Princ. Genetics (ed. 2) v. 82 Epistasis..is similar to dominance except that it occurs between different factors instead of between the two members of an allelomorphic pair. 1965J. A. Serra Mod. Genetics I. iii. 63 Some of the most striking examples of inhibitor-type epistasis are provided by genes which control pigmentation in animals or plants. 1966McGraw-Hill Encycl. Sci. & Technol. II. 327 Each gene may have favorable effects in some combinations and unfavorable effects in others, such as over-dominance and many kinds of epistasis, so that its average effect may be small. |