ac << bk1 << Zhr << bb << bk2
The 5' (distal) end of this breakpoint corresponds to X:382 ,384 and the 3' (proximal) end corresponds to X:382 ,389 (release 6 coordinates). A 6-bp sequence (TTTCGT) from the ac-sc region is present at both breakpoint junctions, suggesting the inversion event created a small, staggered break at the euchromatic end. (FlyBase curator comment: coordinates updated from release 5 coordinates of X:276 ,417.. X:276 ,422 given in paper.)
This breakpoint is within the "1.688" satellite DNA repeat that covers approximately one-half of the X chromosome centric heterochromatin. A 6-bp sequence (TTTCGT) from the ac-sc region is present at both breakpoint junctions, suggesting the inversion event created a small, staggered break at the euchromatic end. (FlyBase curator comment: the coordinates used for this breakpoint correspond to the distal coordinate of the heterochromatin border defined in FlyBase (from FBrf0213099) through to the end of the sequenced chromosome.)
Breakpoint(s) molecularly mapped
Left breakpoint between DNA coordinates 46.8 and 47.9 (Campuzano et al., 1985). 0 is an arbitrarily chosen EcoRI site in the scβ segment of ASC; positive values to the left (Carramolino, Ruiz-Gomez, Guererro, Campuzano and Modolell, 1982, EMBO J. 1: 1185-92).
Mutants are viable and have normal bristle pigmentation.
Weak mutant for sc and shows a Hw effect. variegates for ac, y, and probably l(1)1Ac (Hess, 1962) in X0 male. Left break between ac and sc because induced deficiencies for the terminal uninverted portion of In(1)sc8 are deficient for y and ac but not sc8 (Patterson and Stone, 1935) and because In(1)sc8Lsc4R is deficient for sc (Sturtevant and Beadle, 1936); <up>i.e., for the α subdivision of the sc locus (Garcia-Bellido)</up>. Right break between bb and centromere because deficiencies for terminal genes are frequently deficient for bb (Patterson, 1933, Genetics 18: 32-52) as is In(1)sc4Lsc8R (Gershenson, 1933, J. Genet. 28: 297-313; Sturtevant and Beadle, 1936). In(1)sc8/+ female produces about 3% exceptional sons from 4-strand double crossing over within the inversion and about 8.7% recombination. In(1)sc8/+/Y female produces 19% secondary nondisjunction and 12% recombination (Sturtevant and Beadle, 1936; Grell, 1962, Genetics 47: 1737-54). In(1)sc8/0 partially male lethal (Baker, 1971; Johnson, Harger and Holm, 1979); variegates for y; ac enhanced.
"position-effect variegation for: l(1)1Ac" was stated as tentative.