Edith M. Wallace, unpublished.
Macrochaetae, microchaetae, and trichomes affected
to various degrees depending on allele-short, gnarled, and
bent with ends split or sharply bent. Extreme effect of f36a
on trichomes makes it the most useful allele as a cell marker
in cuticular spots produced by somatic exchange. Treatment
with methylurea causes normal bristle formation (De Marinis).
Developmental studies [Lees and Waddington, 1942, Proc. Roy.
Soc. (London) Ser. B 131: 87-110 (fig.); Lees and Picken,
1945, Proc. Roy. Soc. (London), Ser. B 132: 396-423 (fig.)]
show nature of pupal bristle secretion is affected. Suppression by su(f) and su(Hw)2 allele specific. f1 and f5
suppressed by su(Hw), e(we), su(f), and su(pr), enhanced by
su(s) and su(wa) (Rutledge, Mortin, Schwarz, Thierry-Mieg, and
Meselson, 1988, Genetics 119: 391-97). RK1.
f+ih: forked-wild type in heterochromatin
f+ih with any f allele has normalizing effect.
Patches of bristles and occasionally whole fly is wild type.
An extra Y chromosome enhances the normalizing effect. RK2A.
Expression similar to f but unlike f, does not
respond to su(f). Characterized by a high spontaneous reversion rate (~2 x 10-5); rate may be further increased by a
closely linked cis-dominant mutator allele, Mu(f3N), (5 x;
Woodruff, 1975, Genet. Res. 25: 163-77), by X rays (20 x;
Green, 1977, Mutat. Res. 43: 305-08), and by mustard gas
(Woodruff, Bowman, and Simmons, 1972, Mut. Res. 15: 86-89).
Shows variegated expression of f. More extreme in
combination with E(f). RK2A.
Males have mostly normal bristles, a few reduced
like a Minute, rarely forked. fB27/f are mosaic for forked.
fB27/fB27 females rarely survive; those that do sometimes have
reduced bristles or notched wings, or both, and are sterile.
More extreme in combination with E(f). RK3A.
fX: forked from X irradiation
A medium f. Suppressed by su(f). Behaves as a
hypomorphic allele (Oster, Erlich, and Muller, 1958, DIS
32: 144-45). RK1.