Showing papers in "Journal of Heredity in 1984"

Association of megacolon with a new dominant spotting gene (Dom) in the mouse

Abstract: A new semidominant mutation in the mouse is described. In heterozygotes it produces white spotting and a deficiency of myenteric ganglion cells in the colon and, in homozygotes it is lethal prior to 13 days of gestation. The mutation, called dominant megacolon, symbol Dom, is located on chromosome (chr) 15, 20.6 +/- 1.6 units proximal to Ca. Hairy ears, Eh, a semidominant gene also on chr 15 is shown to have a suppressing effect on crossing over in this section of chr 15.

Anorexia, a recessive mutation causing starvation in preweanling mice

Abstract: A new autosomal recessive lethal mutation in mice, anorexia (anx), located close to pallid (pa) on chromosome (chr) 2, is described. Mutant mice are characterized by growth failure, an emaciated appearance, and abnormal behavior including headweaving, body tremors, uncoordinated gait, and hyperactivity during the late preweanling period. Data suggest that the mutant mice are not ingesting the levels of nutrients necessary to sustain life. This mutation may provide an important tool for studying the neurobiology of suckling behavior in the preweanling animal.

Genetic control of allozyme variants in mature tissues of white spruce trees

Abstract: A method for extracting enzymes from mature tissues of coniferous specie; was applied to 280 progeny from a controlled mating scheme involving five white spruce (Picea glauca (Moench) Voss) trees. Formal analysis of the genetic control of allozyme polymorphisms at six loci was made with this material. Numerous other loci lacking varia- tion among parental trees also were investigated. Genotypic expression of isozyme loci in two types of diploid tissues and one source of haplold tissue from these plants was con- sistent for those enzyme loci that were common to all tissue types.

Larval foraging behavior in isofemale lines of Drosophila melanogaster and D. pseudoobscura

Abstract: Isofemale lines of Drosophila, recently sampled from nature, were used to study the withinand between-line phenotyplc variability of a preadult behavior. The locomotory component of larval foraging behavior was quantified by measuring the length of the path traversed by a foraging 3rd Instar larva on a yeasted dish. Significant between-line variation for this behavior was found in Drosophila melanogaster and in D. pseudoobscura. Matings between lines with extreme phenotypes indicated a relatively simple genetic basis for differences in larval foraging behavior.

Zinc metabolism in lethal-milk mice Otolith, lactation, and aging effects

Abstract: Lethal-milk (lm), a recessive mutation, occurred in the C57BL/6J inbred strain of mice. Lactating lm dams produce a zinc-deficient milk that is lethal to all nursing pups. If foster-nursed on normal dams, lm pups survive and become reproductively mature. Injection of zinc-glycinate into the pups or zinc supplementation of the water of the lactating dams reduces lethality. Other pleiotropic effects in lm mice include congenital otolith defects with delayed righting, "tail-spinning," and abnormal swimming. These effects are diagnostic criteria for segregation of lm mice among backcross progeny. About 40 percent of the expected number of lm pups survive to weaning. Zinc supplementation of the dam improves development of saccular but not of utricular otoliths; zinc does not improve survival of the lm pups among backcross progenies. The lm mice over eight months of age also exhibit extensive hair loss, dermatitis, and skin lesions. Possible roles of metallothionein in zinc and copper metabolism are discussed in regard to the pleiotropic effects of the lethal-milk mutation.

Inbreeding and reproductive performance in Standardbred horses

Abstract: The relationship between inbreeding and both conception and foaling rates in Standardbred horses (trotters and pacers) was examined for 1194 breeding years. There was a statistically significant (P less than 0.05) trend for conception and foaling rates to decrease with increased inbreeding; however, this relationship accounted for less than 2 percent of the variation. Additionally, the relationship between reproductive performance and inbreeding was not consistent between trotters and pacers. For trotters (F = 0.103) there was a trend for an increase in conception and foaling rates with increased inbreeding, while for pacers (F = 0.074), reproductive performance decreased with increased inbreeding. Overall, inbreeding does not appear to be a significant factor influencing reproductive performance of Standardbred horses.

Variation in pattern of mystacial vibrissae in mice A quantitative study of ICR stock and several inbred strains

Abstract: We report on the variation in the pattern of mystacial vibrissae in ICR mice, of which one-half of the about 600 animals investigated showed one or more supernumerary whiskers (SWs). The SWs and their follicles--in all respects identical to the units of the standard pattern except for their smaller size--occurred at a restricted number of sites. In addition, a limited number of mice from two BALB/c strains were analyzed. Half of them also had one or more SWs, but mainly at one site. Mice of the C3H/HeJ and DBA/2J(a) strains were virtually without SWs, whereas animals from the NMRI strain were standard without exception. Nearly all animals of the C57BL/6J strain lacked between 1 and 4 vibrissae, always from one or two of the same adjacent sites. There was a slight overall predominance for the left side of the face to bear SWs and there was no clear-cut association with sex; the entire population was without obvious defects. The sites where extra or lacking whiskers occur are associated with the lines of fusion between the medial and the lateral nasal fold, and between the latter and the maxillary arch. Where tested, we always found a topologic equivalency between the pattern of the whisker follicles and the contralateral pattern of the "barrels"--multineuronal units in layer IV of the parietal cerebral cortex--whether the pattern was standard, "enriched," or lacking in elements. The data presented in this paper provided a basis for several studies carried out subsequently on animals that are the offspring of those characterized here, studies suggesting that the occurrence of supernumerary and of lacking whiskers has a genetic basis.

Inheritance of UMP synthase in dairy cattle

Abstract: The inheritance of uridine-5'-monophosphate (UMP) synthase in dairy cattle was consistent with a two-allele, single-autosomal-locus model. Two phenotypes were associated with different levels of the enzyme in bovine erythrocytes. The predominant phenotype (assumed normal) had twice the concentration of UMP synthase as the second phenotype (deficient). A one-to-one correspondence between enzyme level and genotype identified one homozygote as normal, the heterozygote as deficient, and the other homozygote as unobserved. Three alternative hypotheses were rejected. The deficiency as homozygous recessive was rejected because 20 matings between assumed normal males and deficient females resulted in 10 normal and 10 deficient offspring. The hypothesis that the deficiency was homozygous dominant was rejected because the 95 percent confidence interval about the observed gene frequency, 0.0024 to 0.0146, did not contain the estimated gene frequency for equilibrium between an average 10(-5) mutation rate and selection against the deficiency as homozygous dominant. Analyses of female relatives implicated one bull as deficient (96 percent probability), as he had, independently, 2 deficient daughters, 5 deficient granddaughters from untested dams, and 3 deficient great-granddaughters from untested ancestors. The hypothesis that the deficiency was sex-linked was rejected because 3 of 9 tested sons of the putative deficient bull were deficient. Calf mortality is expected in 25 percent of matings between deficient animals.

Reciprocal translocations in pigs Their detection and consequences on animal performance and economic losses

Abstract: In France, the national computerized program for sow herd management regularly delivers a listing of hypoprolific boars for which a cytogenetic evaluation is required, and participates in the differential diagnosis of the other causes of reduced prolificacy. Two reciprocal translocations, 4/14 and 7/15, reducing the prolificacy by about 45 percent have been discovered since 1979. A third one, leading to a prolificacy reduction of about 28 percent, is described in the present paper. The effects of translocation 4/14 were studied in an experimental herd, in which the ovulation rate did not seem to be modified and the early embryonic mortality accounted for the decrease in litter size. The growth rate at day 35 was higher in piglets carrying the chromosomal abnormality than in their normal littermates, i.e., 215 vs. 182 g per day (P less than 0.10). The economic consequences of using a boar carrying a translocation on a group of 21 sows were estimated by means of a simulation model "Porsim." When prolificacy decreased by five piglets per litter, the losses represented 157 piglets, i.e., about $4000. If, in addition to this, the percentage of non-returns into heat decreased by 35 percent, the losses then represented 248 piglets, i.e., $6000. Because of this important economic risk, it is suggested that measures be taken to detect defective animals and to prevent their use.

Situs inversus in homozygous mice without immotile cilia

Abstract: Mice homozygous for the mutation situs inversus, iv, are characterized by situs inversus in 50 percent of the individuals. We have investigated the ultrastructure and motility of tracheal cilia and sperm tails in homozygous individuals with and without situs inversus. We found no abnormalities of ciliary structure. Therefore, ciliary immotility is not an essential correlate of situs inversus.

Genetics of the fawn-hooded rat strain The coat color dilution and platelet storage pool deficiency are pleiotropic effects of the autosomal recessive red-eyed dilution gene

Abstract: The inheritance of coat color, hooded-coat pattern, and platelet storage pool deficiency of fawn-hooded rats was studied by crossing fawn-hooded rats with rats of other strains. It was determined that the tan coat color and the platelet storage pool deficiency were pleiotropic effects of the autosomal recessive red-eyed dilution (r) gene. The hooded-coat pattern was determined to be the effect of a different autosomal recessive gene. It also was demonstrated that the tan coat color of fawn-hooded rats is a dilution and that the shade of the tan coat color expressed varied with the underlying coat color genes.

Detection and prevalence of UMP synthase deficiency among dairy cattle

Abstract: A partial deficiency of UMP synthase has been detected in Holstein dairy cattle. Since affected females secrete milk with elevated concentrations of orotate, milk orotate was used to screen for the condition among 880 cows in 17 randomly selected Holstein herds in Illinois. Mean orotate was 85.0 +/- 1.5 microgram/ml milk and 17 cows had milk orotate in excess of 170 micrograms/ml. Including the latter animals, 42 cows were evaluated for erythrocyte UMP synthase and 15 were found to be partially deficient. Thus, at least 1.7 percent of all cows had the condition; this is a minimal estimate because the initial screen was milk orotate and this may be low, particularly early in lactation. Deficient cows had half the level of UMP synthase as normal, nondeficient cows (1.30 +/- 0.06 vs. 2.79 +/- 0.10 units/ml). The binomial classification of deficient versus normal accounted for 72 percent of the variation noted in UMP synthase. Milk orotate was significantly elevated in deficient cows (337.8 +/- 31.3 micrograms/ml), validating its use as a screening device. Urinary orotate also was higher for deficient cows (28.4 +/- 5.2 vs. 9.2 +/- 0.8 micrograms/ml) and differentiated the two groups as well as milk orotate. Normal and deficient cows did not differ in milk lactose concentrations. Erythrocyte UMP synthase also was measured in 85 Holstein bulls used for artificial insemination and 6 had low levels of UMP synthase (1.39 +/- 0.19 vs. 2.92 +/- 0.05 units/ml); the binomial classification accounted for 42 percent of the variation. The partially deficient animals identified appear to be heterozygotes for a condition expected to be lethal in the homozygous state.

Trace metals and otolith defects in mocha mice

Abstract: Mocha mice with pigment anomalies of the coat, eyes, and inner ears also have congenital otolith defects, and they exhibit progressive cochlear degeneration. Mocha mice were first reported to exhibit otolith defects comparable to those of pallid mice. Since manganese supplementation is effective in preventing the otolith defects in pallid mice and in pastel mink, we sought to establish whether or not manganese also might be effective in mocha mice. The otolith defects of mocha mice were prevented or reduced by supplementing the pregnant dams with manganese and/or zinc. The mocha mice also exhibited high perinatal mortality that was not reduced by the supplementary metals. Surviving mocha mice have behavioral anomalies associated with their inner ear defects. Preliminary observations of auditory-evoked brainstem responses and of cochlear degeneration in the mocha mice are discussed.