Abstract
1. Forty-two mutant characters of Drosophila ananassae, which were newly found, following the first eleven mutants, are described, with their origins, characteristics, and linkage data.
2. Of these mutants, thirteen are sex-linked. They are achaete (ac), clumploid (cl), cut3 (ct3), extended-b (ex-b), Golf (Gf), lethal-3 (l-3), lethal-4 (l-4), purplish (ph), scute (sc), scute2 (sc2), scute3 (sc3), vesiculated (vs), and yellow (y). Although not separable from the heterozygous flies, the homozygotes of Golf, a dominant character, are viable.
3. Beaded (Bd), broken-b (bn-b), chilblained (ch), contracted (cnt), crippled (cp), Dichaete (D), extended (ex), hooked (hk), missing (ms), missing-b (ms-b), Minute-IIb (M-IIb), Off (Off), Puffed (Pu), roof (rf), and rough (ro) are described as mutants in the second chromosome. Among the dominant genes, Off was known to be viable when homozygous. As to the rough gene, it was peculiar in that the character could be expressed only when accompanied with a Plexate gene.
4. In the third chromosome, there newly appeared nine mutants, such as crooked-b (ck-b), erect (er), Minute-IIIc (M-IIIc), Minute-IIId (M-IIId), rumpled (rm), rippled (rp), pski-III (sk-III), warped (wp), and wavy (wy).
5. Bobbed-IV (bb-IV), which was first described as bobbed, has long been known to be only a mutant found in the fourth chromosome. Three mutant genes are newly added, namely, Minute-IVa (M-IVa), mottled (mo), and Shaven (Sv).
6. A certain power to enhance crossing over, affecting both sexes, seems to be associated with every Minute-IIb, Minute-IIIc, and Minute-IVa, with the result that provided any one of these Minutes are associated, the male crossing over occurs in the natural condition, whereas in the female associated with any one of these Minutes, crossing over is increased.
7. Various kinds of inversion seem to appear quite often in this species. Puffed, perhaps also Dichaete and Beaded, should be accompanied with inversion CIIL, a subterminal inversion having the power to suppress crossing over in the left arm of the second chromosome, while a small inversion may be associated with the X-chromosome of lethal-4 or w f2, which, however, has not yet been recognized cytologically, only showing that it may suppress crossing over slightly at the region near w f2.
