. Contributions to the genetics of Drosophila melanogaster. Drosophila melanogaster; Heredity; Karyokinesis. GENES MODIFYING NOTCH. 383 Truncate is a mutant that frequently appears in our cultures. It has also appeared in the selection experiments. The of the wings are cut off squarely. As it is dominant, esjK'ciiilly in certain stocks, it is hkely that it would much effect the character of the Notch when it occurred with it. Truncate appeared several times in the course of the experiment. The character of the trun- cate Notch flies is shown in figure 103, a, b, c, d. Beaded has appeared
. Contributions to the genetics of Drosophila melanogaster. Drosophila melanogaster; Heredity; Karyokinesis. GENES MODIFYING NOTCH. 383 Truncate is a mutant that frequently appears in our cultures. It has also appeared in the selection experiments. The of the wings are cut off squarely. As it is dominant, esjK'ciiilly in certain stocks, it is hkely that it would much effect the character of the Notch when it occurred with it. Truncate appeared several times in the course of the experiment. The character of the trun- cate Notch flies is shown in figure 103, a, b, c, d. Beaded has appeared sev- eral times in the course of the work (fig. 104),and while no tests have been made to establish its relation to stock beaded, it is not unlikely that it is sometimes the same. Since beaded often affects the ends of the wings, and since Notch itself often has a de- fective outer margin to the wing, the similarity of the two stocks is in some flies very striking. But the common beaded is not sex-hnked. A stock which, when crossed to vestigal, produces flies many of which have a Notch on the end of the wings has been isolated by Dr. C. B. Bridges. It has no relation to Notch and appears in both sexes. (See "Nick," page 273, Part II.) On several occasions males (also females) have been found in which a Httle piece is cut out from the end of one or from both wings, (fig. 105 a, 5, c). Superficially one gets the impression that the Notch character has appeared in a male. These males have l)een bred, and have never transmitted the character, so that there can be no doubt that the variation has nothing whatever to do with Noteh and is possibly only a somatic defect, or more probably is a nuiltiple-factor character. The only way, in fact, that Notch might appear in a nuile would be through somatic segregation in a female embryo of such a kind that the Notch-bearing chromosome became dislocated and car- ried to the anlage of the wing, leaving the other chromosome to j)ro(l
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