Confirmation of the presence of a major gene for fecundity in Thoka Cheviot sheep by segregation analyses

The putative Thoka gene, with large effects on fecundity, originated in Icelandic sheep. The gene was introduced to the UK in 1985 through a programme of crossbreeding and established in Cheviot sheep (Russel et al., 1997). Ewes have been retained in the flock as putative Thoka gene carriers if they have lambed in each of the first three years and had at least two sets of twins. Progeny tests on a separate population of ewes have been used on two occasions to identify rams believed to carry the gene. Despite this complex breeding programme, the actual segregation of a gene for fecundity has yet to be unambiguously demonstrated in this flock. The purpose of this study is to use complex segregation analysis to demonstrate the existence of this gene, estimate the size of its effect and frequency of the favourable allele within the population.

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Autosomal Dominant Gene Transmission in a Large Kindred with Gilles de la Tourette Syndrome

The British Journal of Psychiatry ◽

10.1192/bjp.160.6.845 ◽

1992 ◽

Vol 160 (6) ◽

pp. 845-849 ◽

Cited By ~ 51

Author(s):

David Curtis ◽

Mary M. Robertson ◽

Hugh M. D. Gurling

Keyword(s):

Linkage Analysis ◽

Genetic Markers ◽

Segregation Analysis ◽

Autosomal Dominant ◽

Major Gene ◽

Dominant Gene ◽

Incomplete Penetrance ◽

Complex Segregation Analysis ◽

Diagnostic Instruments ◽

Autosomal Dominant Fashion

A multiplex kindred ascertained through a single proband with GTS has been systematically investigated with standardised diagnostic instruments for other cases of GTS and related disorders. Complex segregation analysis supported the hypothesis that a single major gene inherited in autosomal dominant fashion but with incomplete penetrance contributed most of the variance in the liability to develop GTS and related disorders. This result is consistent with previous segregation analyses which have employed different methods of ascertainment, and tends to confirm that a proportion of GTS is due to a dominant gene and is suitable for investigation with genetic markers for linkage analysis.

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Inheritance of litter size at birth in the Brazilian grass mouse (Akodon cursor, Sigmodontinae, Rodentia)

Genetics Research ◽

10.1017/s0016672302005724 ◽

2002 ◽

Vol 80 (1) ◽

pp. 55-62 ◽

Cited By ~ 5

Author(s):

YU. S. AULCHENKO ◽

L. O. ARARIPE ◽

P. S. D'ANDREA ◽

A. A. SHISHKIN ◽

R. CERQUEIRA ◽

...

Keyword(s):

Genetic Analysis ◽

Litter Size ◽

Significant Influence ◽

Segregation Analysis ◽

Genetic Factors ◽

Major Gene ◽

Gene Model ◽

Complex Segregation Analysis ◽

Size At Birth

By means of complex segregation analysis we studied the inheritance of litter size in two large pedigrees of captive-bred colonies of the Brazilian grass mouse Akodon cursor. Genetic analysis has revealed a highly significant influence of genetic factors on the variation of litter size (heritability, h2, was estimated as 0.44). The inheritance followed the classical polygene model: neither the major-gene model nor the polygene with unequal contribution model described the data significantly better.

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Complex Segregation Analysis Provides Evidence for Autosomal Dominant Transmission in the Chinese Han Families with Ankylosing Spondylitis

BioMed Research International ◽

10.1155/2017/4515701 ◽

2017 ◽

Vol 2017 ◽

pp. 1-6

Author(s):

Yutong Jiang ◽

Qing Lv ◽

Shaoqi Rao ◽

Zetao Liao ◽

Pingping Zhang ◽

...

Keyword(s):

Ankylosing Spondylitis ◽

General Model ◽

Segregation Analysis ◽

Familial Aggregation ◽

Major Gene ◽

Dominant Mode ◽

Chinese Han ◽

Complex Segregation Analysis ◽

Familial Association ◽

Mode Of Inheritance

Introduction. Familial aggregation of ankylosing spondylitis (AS) has been frequently noticed. However, the mode of inheritance in AS remains poorly understood. Our aim was to determine the mode of inheritance best fitting the observed transmission pattern of AS families. Methods. Families with 5 or more AS patients diagnosed with 1984 modified New York criteria were recruited. We performed complex segregation analysis for a binary trait in regressive multivariate logistic models. The inheritance models, including sporadic, major gene, environmental, general, and other 9 models, were compared by likelihood ratio tests and Akaike’s Information Criterion. Results. This research included 9 Chinese Han AS families with a total number of 315 persons, including 74 patients. First, familial association was determined. Sporadic with familial association model was rejected when compared with either the general model or the homogeneous general model (p<0.001). The environmental model was also rejected when compared with general models (p<0.02). Mendelian dominate mode fitted best in 5 AS families, while Tau AB free model best explained the mode of inheritance in these AS families. Conclusion. This study provided evidence in support of Mendelian dominant mode and firstly discovered a non-Mendelian mode called tau AB free inheritance mode in AS.

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Analyses for the Presence of a Major Gene Affecting Uterine Capacity in Unilaterally Ovariectomized Rabbits

Genetics ◽

10.1093/genetics/163.3.1061 ◽

2003 ◽

Vol 163 (3) ◽

pp. 1061-1068 ◽

Cited By ~ 1

Author(s):

M J Argente ◽

A Blasco ◽

J A Ortega ◽

C S Haley ◽

P M Visscher

Keyword(s):

High Frequency ◽

Segregation Analysis ◽

Major Gene ◽

Reproductive Traits ◽

Large Contribution ◽

Embryo Survival ◽

Fetal Survival ◽

Complex Segregation Analysis ◽

Bartlett’S Test ◽

Estimated Breeding Values

Abstract The presence of a major gene for uterine capacity (UC), ovulation rate (OR), number of implanted embryos (IE), embryo survival (ES), fetal survival (FS), and prenatal survival (PS) was investigated in a population of rabbits divergently selected for UC for 10 generations. Selection was performed on estimated breeding values for UC up to four parities. UC was estimated as litter size in the remaining overcrowded horn of unilaterally ovariectomized does. OR and IE were counted by means of laparoscopy. Bartlett’s test, Fain’s test, and a complex segregation analysis using Bayesian methods were used to test for the presence of a major gene. All three tests showed that the data appeared consistent with the presence of a major gene affecting UC and IE. The results of the complex segregation analysis suggested the presence of a major gene with large effect on IE and ES (a > 1σp), at high frequency (p = 0.70 and 0.68, respectively), and with a large contribution to the total variance (Rg = 0.39 and 0.47, respectively); and the presence of a major gene with moderate effect on each of OR, FS, PS, and UC. The results suggest that the studied reproductive traits are determined genetically by at least one gene of large effect.

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