| 释义 |
ˈtest-cross, n. and v. Genetics.
[f. test n.1 + cross n.]
A. n. A cross between an individual whose genotype for a certain trait is unknown and one that is homozygous recessive for that trait, so that the unknown genotype may be determined from that of the offspring.
1934C. B. Bridges in Jrnl. Heredity XXV. 18 The type of cross designated..as the ‘backcross’ is here to stay... Because of this characteristic we may employ the term ‘testcross’ wherever ‘backcross’ has been used in the special meaning. 1979Arms & Camp Biology xiii. 198 If the red-flowered plant of unknown genotype were actually heterozygous (Rr), half the offspring of the test cross would be expected to be white-flowered and half red-flowered.
B. v. trans. To make the subject of such a cross.
1950E. W. Sinnott et al. Princ. Genetics (ed. 4) iii. 68 The trihybrid with round and yellow seeds and colored flowers.., when test-crossed to plants with wrinkled, green seeds and white flowers..will produce 8 combinations. 1978Nature 27 July 317/1 A proportion of the males from a wild population in Texas showed low levels of recombination when heterozygous males were test-crossed to homozygous marked females. |