ON THE INHERITANCE OF INTERSEXUALITY IN SWINE

1980 ◽  
Vol 22 (4) ◽  
pp. 507-527 ◽  
Author(s):  
K. Sittmann ◽  
A. J. Breeuwsma ◽  
J. H. A. te Brake
Keyword(s):  
Sex Ratio ◽  
Litter Size ◽  
Major Gene ◽  
Hormone Treatment ◽  
Segregation Ratio ◽  
Normal Female ◽  
Mating Types ◽  
Polygenic Inheritance ◽  
Parsimonious Explanation ◽  
Duplicate Epistasis

Data of Breeuwsma (1970) were analyzed in an attempt to discriminate between major gene vs. multifactorial modes of inheritance of intersexuality in swine. Of 3708 females, 160 were intersexes with external phenotypes ranging from normal female (normal overlap) to testicular pseudohermaphrodite. Environment (litter size, parity, hormone treatment of dam) influenced detection of carriers but not origin of intersexes. Normal overlaps lowered penetrance, partly due to deaths in competition with male littermates. Phenocopies (intersex with unusual genotype or with karyotype other than 38,XX) were rare. Sex ratio variation between mating types could be ascribed to the ascertainment method. Segregation ratio estimates for female sibships increased from those with at least one to those with at least two intersexes less than expected for polygenic inheritance. The latter could not be ruled out (heritability of liability by three methods was 78%), but duplicate epistasis provided a more parsimonious explanation. Separation of litters from retrospectively known carriers into identifying and post-identifying groups produced patterns of segregation estimates supporting inheritance by few rather than many genes. Crossbred intersexes indicate homology of genes for intersexuality in several European breeds of pigs.

Reproductive Biology of the Black Dogfish,Centroscyllium Fabricii, Collected From Waters off Western Greenland

1995 ◽  
Vol 75 (2) ◽  
pp. 285-310 ◽  
Author(s):  
Kazunari Yano
Keyword(s):  
Sex Ratio ◽  
Reproductive Biology ◽  
Breeding Season ◽  
Litter Size ◽  
Reproductive Organs ◽  
Normal Female ◽  
Size At Maturity ◽  
Free Living ◽  
Near Term ◽  
Female Reproductive Organs

The reproductive biology of 1124 male (165–760 mm TL) and 1476 female (175–898 mm TL) black dogfish,Centroscyllium fabricii, was examined. The sharks were caught off western Greenland with bottom otter trawls. Size at maturity was about 550 mm TL in males and 650 mm TL in females. Ovarian ova did not continue to develop during gestation. The sex ratio of embryos was 1:1. Litter size ranged from 4 to 40, with a mean of 16–4. The total number of mature ova, fertilized ova, or embryos tended to increase with size of the females. Development of black dogfish embryos is dependent solely on yolk reserves. Near-term embryos (152–192 mm TL) had completely absorbed their external yolk sacs. The smallest free-living specimens collected in this study were 165 mm TL for males and 175 mm TL for females. The black dogfish does not seem to have a well-defined breeding season. This species displayed a well-defined pattern of depth segregation by size. The sex ratios in five shallow depth strata (500–599, 600–699, 700–799,800–899, and 900–999 m) were 1:1, but those of three deeper depth strata (1000–1099,1100–1199, and 1200–1299 m) contained a significantly greater number of females than males. Four abnormal hermaphrodites possessed gonads containing both testicular and ovarian tis-sues. Two specimens had normal female reproductive organs (e.g. ovaries, oviducts, nidamental glands, and uteri) as well as claspers.

scholarly journals Polymorphism Detection of GDF9 Gene and Its Association with Litter Size in Luzhong Mutton Sheep (Ovis aries)

Animals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 571
Author(s):  
Fengyan Wang ◽  
Mingxing Chu ◽  
Linxiang Pan ◽  
Xiangyu Wang ◽  
Xiaoyun He ◽  
...  
Keyword(s):  
Litter Size ◽  
Tertiary Structure ◽  
Novel Mutation ◽  
Major Gene ◽  
Ovis Aries ◽  
Nucleotide Polymorphisms ◽  
Economic Traits ◽  
Coding Region ◽  
Association Analyses ◽  
Gdf9 Gene

Litter size is one of the most important economic traits in sheep. GDF9 and BMPR1B are major genes affecting the litter size of sheep. In this study, the whole coding region of GDF9 was sequenced and all the SNPs (single nucleotide polymorphisms) were determined in Luzhong mutton ewes. The FecB mutation was genotyped using the Sequenom MassARRAY®SNP assay technology. Then, the association analyses between polymorphic loci of GDF9 gene, FecB, and litter size were performed using a general linear model procedure. The results showed that eight SNPs were detected in GDF9 of Luzhong mutton sheep, including one novel mutation (g.41769606 T > G). The g.41768501A > G, g.41768485 G > A in GDF9 and FecB were significantly associated with litter size in Luzhong mutton ewes. The g.41768485 G > A is a missense mutation in the mature GDF9 protein region and is predicted to affect the tertiary structure of the protein. The results preliminarily demonstrated that GDF9 was a major gene affecting the fecundity of Luzhong mutton sheep and the two loci g.41768501A > G and g.41768485 G > A may be potential genetic markers for improving litter size.

Ambient Temperature and Rainfall: An Effect on Sex Ratio and Litter Size in Deer Mice

1985 ◽  
Vol 66 (2) ◽  
pp. 289-298 ◽  
Author(s):  
P. Myers ◽  
L. L. Master ◽  
R. A. Garrett
Keyword(s):  
Sex Ratio ◽  
Ambient Temperature ◽  
Litter Size ◽  
Deer Mice

Maximization of long-term productivity in a rat colony

1972 ◽  
Vol 6 (2) ◽  
pp. 203-206 ◽  
Author(s):  
N. T. Gridgeman ◽  
J. M. Taylor
Keyword(s):  
Sex Ratio ◽  
Litter Size ◽  
Albino Rats ◽  
Mathematical Treatment ◽  
Production Time ◽  
Time Curve ◽  
Intensive Breeding

Maximization of intensive breeding in the animal colony can be approached using a simple mathematical treatment of the production-time curve. It has been found that in a colony of specified-pathogen-free albino rats whose breeding dams were averaging litters of 11 at 6-week intervals, the stock should be entirely replaced at intervals of 27-28 weeks to maximize the output of weanlings. Some data on litter size and sex ratio are also presented.

scholarly journals Somatic development and embryo yield in crossbred F1 mice generated by different mating strategies

2010 ◽  
Vol 70 (1) ◽  
pp. 145-149 ◽  
Author(s):  
RITP. Batista ◽  
S. Wohlres-Viana ◽  
ISB. Pinto ◽  
VV. Maffili ◽  
JHM. Viana
Keyword(s):  
Litter Size ◽  
Inbreeding Depression ◽  
Hormone Treatment ◽  
Response Variability ◽  
Mating Strategies ◽  
Corpora Lutea ◽  
Parental Effect ◽  
Crown Rump Length ◽  
Somatic Development ◽  
Embryo Yield

The aim of this study was to evaluate different mating strategies among endogamic strains to create F1 populations of mice, minimising the effect of inbreeding depression on somatic development and embryo yield. Females from the strains Swiss, CBA and C57Bl/6 were divided in nine experimental mate arrangements. The total numbers of pups born alive per dam and somatic development, estimated by weighing and measuring the crown-rump length, were recorded. Superovulation response was evaluated in outbreed females. Litter size differed among endogamic dams, irrespective of the sire. Somatic development results suggest heterosis and imprinting phenomena, once a differential parental effect was demonstrated. There was no difference in corpora lutea, ova or embryos recovered (P > 0.05), but recovery and viability rates differ among F1 groups (P < 0.05). The association of dam prolificity with somatic development and superovulation response of the pups should be considered for experimental F1 populations establishment. The use of outbreed animals, however, did not reduce response variability to hormone treatment.

Twinning and fetal sex ratio in moose: effects of maternal age and mass

1997 ◽  
Vol 75 (11) ◽  
pp. 1945-1948 ◽  
Author(s):  
T. Nygrén ◽  
I. Kojola
Keyword(s):  
Sex Ratio ◽  
Litter Size ◽  
Female Competition ◽  
Offspring Sex Ratio ◽  
Female Age ◽  
Maternal Characteristics ◽  
Low Degree ◽  
Offspring Sex ◽  
Limited Food ◽  
Female Bias

To evaluate hypotheses concerning the effects of maternal characteristics on litter size and offspring sex ratio in a polygynous mammal, we examined how female age and mass affected the number and sex ratio of fetuses in moose (Alces alces). We analysed 420 fetuses collected from 297 females killed in Finland. Females that carried two fetuses were older than females with one fetus, while mass did not affect litter size. Sex ratio was not conclusively linked with maternal quality. The overall lack of difference in the sex ratio (no male bias among fetuses carried by the heaviest females) can be explained by the rather low degree of polygyny and the lack of intense female – female competition for a limited food supply (no female bias among fetuses carried by the heaviest females).

The Genetics of Bipolar Disorder

1993 ◽  
Vol 27 (4) ◽  
pp. 560-580 ◽  
Author(s):  
Philip Mitchell ◽  
Andrew Mackinnon ◽  
Brent Waters
Keyword(s):  
Bipolar Disorder ◽  
Psychiatric Disorders ◽  
Dna Markers ◽  
Major Gene ◽  
Adoption Studies ◽  
Polygenic Inheritance ◽  
Current State ◽  
Number Of Genes ◽  
Mode Of Transmission ◽  
Molecular Biological Techniques

Growing interest in the application of molecular biological techniques to psychiatric disorders has reinvigorated interest in the genetics of the psychoses. It is therefore timely to review the current state of knowledge of the genetics of bipolar disorder. Family, twin and adoption studies are all consistent in confirming the strongly heritable nature of this condition. As segregation analyses have been unable to determine the mode of transmission of bipolar disorder, ongoing linkage analyses using DNA markers will be crucial in determining whether this condition is due to a single major gene, a small number of genes, or multifactorial polygenic inheritance.

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