Localisation of a dystrophin-related autosomal gene to 6q24 in man,and to mouse chromosome 10 in the region of the dystrophia muscularis (dy) locus

Summary We have localised a dystrophin-related autosomal gene called DMDL (Duchenne muscular dystrophy-like) to human chromosome 6q24 by in situ hybridisation. Using restriction fragment length polymorphism analysis in two mouse species, we have localised the homologous gene Dmdl in the mouse to chromosome 10 proximal to the Myb oncogene. A neuromuscular disease locus dystrophia muscularis (dy) has previously been assigned to this region of mouse chromosome 10.     

Athymic mice of the 101/HY strain with a new allele at the nude locus]

The spontaneous autosomal recessive mutation at locus nude (nuY) was discovered in 101/HY mice imperfect in respect to repair of induced chromosome damage and this is maintained in conventional conditions at RLEBM. Homozygous mutants have no hair and thymic differentiation. The new mutant form can be a valuable model for medical and biological experiments requiring T-cell immune deficiency.     

A survey of cultivated heirloom tomato varieties identifies four new mutant alleles at the green-flesh locus

The process of crop domestication occurs through the selection and subsequent propagation of novel alleles that improve traits of interest. Cultivated tomato (Solanum lycopersicum), particularly heirloom varieties, exhibit a wide range of variation in fruit size, shape and color. The green-flesh mutant of tomato possesses a stay-green phenotype resulting in fruits that ripen to a red-brown color, due to the retention of chlorophyll and the simultaneous accumulation of lycopene. The recent identification of the GREEN-FLESH gene provides a molecular tool with which to investigate the origin of a subset of cultivated tomato varieties that resemble the green-flesh mutant. Sequence analysis of the GF locus from 26 varieties revealed the existence of four previously unidentified null alleles. This study illustrates the potential of cultivated tomato varieties, including heritage cultivars, heirlooms, and land races, for uncovering new alleles in genes of interest.     

Differential effects of two alleles of the dy locus on the pituitary-testicular axis of mice.

Testicular function was studied in vivo and in vitro in adult male dy/dy and dy2J/dy2J dystrophic mice. The results demonstrate that testicular function in dy/dy mice is more affected. The basal levels of pituitary hormones measured were normal in dystrophic mice, except for the presence of hyperprolactinemia in dy/dy mice. In dy/dy mice testicular weight was diminished and a deficient transduction of the gonadotropic signal is present in vivo, accompanied by reduced efficiency of 17-hydroxylase and 17-hydroxysteroid dehydrogenase. In dy2J/dy2J mice the signal transduction is normal and the reduction in enzyme efficiency is limited to 17-hydroxysteroid dehydrogenase. The in vitro HCG-induced increases in production of testosterone (T) and estradiol (E2) were reduced in dy/dy/mice, and the data indicate a reduction of enzyme activity rather than in efficiency. In dy21/dy21/mice, HCG-induced T synthesis was increased, HCG-induced E2 synthesis was normal, but basal media E2 levels were reduced, with the in vitro efficiency of aromatase being suppressed under both basal and HCG-stimulated conditions, when compared to their normal littermates.     

A new allele at the Pgd locus in pigs

A new electrophoretic variant of porcine 6-phosphogluconate dehydrogenase (PGD) is described. The new variant, PGD C, has been shown to be controlled by a third allele, PgdC, at the Pgd locus.     

A new polymorphic restriction site at the human atrial natriuretic peptide (hANP) gene locus

A unique two allele polymorphism for both HpaII and SmaI is described in the second intron of the human atrial natriuretic peptide gene. It should be a useful marker of this candidate gene in familial susceptibility to hypertension.     

A new locus (H-2T) at theD end of theH-2 complex

A.TH (H-2 ^t2) anti-A.TL (H-2 ^t1) effectors, obtained after in vitro restimulation of in vivo sensitized cells, react in the CML assay not only withH-2 ^t1, but also with a number of other targets carrying unrelatedH-2 haplotypes. The broad cross-reactivity can be explained by postulating the presence among the effectors of at least two populations of cells, one reacting with antigens controlled by theI region, and the other directed against antigens controlled by a locus at theD end, outside theH-2 complex. The existence of the two cell populations is also supported by cold-target inhibition data. The locus coding for the D-end CML antigens maps betweenQa-2 andTla. The locus is assigned the symbolH-2T. TheH-2T-locus CML is seen only after in vivo presensitization, but the killing is not K/D-restricted.     

Adh n5: A temperature-sensitive mutant at the Adh locus in Drosophila

Individuals of an alcohol dehydrogenase-negative strain of Drosophila melanogaster designated Adh ⁿ⁵ are resistant to ethanol poisoning at low but not at high temperatures. The basis for this behavior is that Adh ⁿ⁵ flies contain a mutant form of alcohol dehydrogenase which is less heat stable than that of wild-type flies. The mutation in Adh ⁿ⁵ maps at, or very close to, the presumptive structural locus and is not complemented by any of 11 other alcohol dehydrogenase-null mutants.This research was supported by Grant No. GM 18254 from the National Institutes of Health and Grant No. M55.2217 from the National Cancer Institute.Publication No. 768 from the Department of Biology, Johns Hopkins University.     

A new polymorphic pepsinogen locus (Pg-2) in the rat (Rattus norvegicus)

Only two types of pepsinogens, which are products of the Pg-1 locus, are present in rat urine. In gastric mucosa, however, additional pepsinogen isozymes are expressed. We have found a polymorphism for rat gastric mucosa pepsinogen using agarose gel electrophoresis. Some inbred rat strains expressed a pepsinogen band, while others did not. The trait was found to be controlled by a single autosomal locus. We tentatively designated the locus as Pg-2 with two alleles, Pg-2a for the one controlling presence of the band and Pg-2o for the one controlling absence. Linkage analysis using BN and TM strains revealed that Pg-2 was closely linked to Pg-1 (3.7 +/- 1.8 cM), and that it did not belong to LG I (Hbb and p), LG II (Acon-1 and Mup-1), LG IV (Hao-1 and Svp-1), LG V (Es-1 and Es-3), LG VI (Gc and h), LG IX (RT1), LG X (Fh and Pep-3), nor a LG containing Ahd-2 (as yet undetermined).