The frequency of males (5AA; XO) among the self progeny of wild-type @entity2199 hermaphrodites (5AA; XX) is about one in 500. Fifteen him (for "high incidence of males") mutations have been identified that increase this frequency by a factor of ten to 150, as a result of increased X-chromosome nondisjunction. The mutations define ten complementation groups, which have been mapped: nine are autosomal, and one sex linked. Most of the mutants are superficially wild type in anatomy and behavior; however, @entity69901 mutants display @entity10844 , and @entity68079 mutants, which have a Him phenotype, exhibit a variety of anatomical and @entity146 . All the mutants segregate fertile 3X hermaphrodite progeny as well as XO male progeny. Some produce large numbers of inviable zygotes. Mutants in all ten genes produce diplo-X and nullo-X exceptional ova, and in the four strains tested, diplo-X and nullo-X exceptional sperm are produced by 2X "transformed" males. It appears likely that most of the mutants have defects in both gamete lines of the hermaphrodite. XO males of him strains other than @entity69901 and @entity68079 are similar to wild-type males in anatomy and behavior, and all produce equal or almost equal numbers of haplo-X and nullo-X sperm, and no diplo-X sperm. Male fertility is reduced to varying extents in all him mutants. In four of the strains, nondisjunction during oogenesis has been shown to occur at a reductional division, and in three of these strains, abnormalities in recombination have been demonstrated. One mutant also exhibits autosomal nondisjunction, but many of the others probably do not. Therefore, the X chromosome of @entity2199 may differ from the autosomes in the mechanisms controlling its meiotic behavior.--3X hermaphrodites are shorter and less fertile than 2X hermaphrodites, and they produce many inviable zygotes among their self progeny: these are probably 4X zygotes. Haplo-X and diplo-X ova are produced in 2:1 ratio by 3X hermaphrodites. him mutations are expressed in these animals, increasing the frequency of self-progeny males and 2X hermaphrodites.

Nondisjunction Mutants of the XXXX @entity2199 .

@entity2199 :: ('6239', 'Species') :: ['C. elegans', 'Caenorhabditis elegans'] @entity10844 :: ('MESH:D006058', 'Disease') :: ['gonadal abnormalities'] @entity146 :: ('MESH:D001523', 'Disease') :: ['behavioral abnormalities'] @entity69901 :: ('181187(Tax:6239)', 'Gene') :: ['him-4'] @entity68079 :: ('176157(Tax:6239)', 'Gene') :: ['unc-86']
@entity2199 :: (6239,Species) :: ['Nematode']
