Evidence for a Possible Major Gene Effect in Absolute Finger Ridge Count

1973 ◽  
Vol 23 (5) ◽  
pp. 414-421 ◽  
Author(s):  
M.A. Spence ◽  
R.C. Elston ◽  
K.K. Namboodiri ◽  
W.S. Pollitzer
Keyword(s):  
Major Gene ◽  
Ridge Count ◽  
Gene Effect ◽  
Major Gene Effect

scholarly journals A Major Gene Effect Controls Resistance to Caries

2011 ◽  
Vol 90 (6) ◽  
pp. 735-739 ◽  
Author(s):  
R.I. Werneck ◽  
F.P. Lázaro ◽  
A. Cobat ◽  
A.V. Grant ◽  
M.B. Xavier ◽  
...  
Keyword(s):  
Major Gene ◽  
Gene Effect ◽  
Major Gene Effect

Segregation analysis of idiopathic scoliosis: Demonstration of a major gene effect

1999 ◽  
Vol 86 (4) ◽  
pp. 389-394 ◽  
Author(s):  
T.I. Axenovich ◽  
A.M. Zaidman ◽  
I.V. Zorkoltseva ◽  
I.L. Tregubova ◽  
P.M. Borodin
Keyword(s):  
Idiopathic Scoliosis ◽  
Segregation Analysis ◽  
Major Gene ◽  
Gene Effect ◽  
Major Gene Effect

Detection of a major gene for litter size in Thoka Cheviot sheep using Bayesian segregation analyses

2002 ◽  
Vol 75 (3) ◽  
pp. 339-347 ◽  
Author(s):  
G. A. Walling ◽  
S. C. Bishop ◽  
R. Pong-Wong ◽  
G. Gittus ◽  
A.J. F. Russel ◽  
...  
Keyword(s):  
Litter Size ◽  
Variance Components ◽  
Fixed Effects ◽  
Major Gene ◽  
Single Copy ◽  
Threshold Analysis ◽  
Data Set ◽  
Gene Effect ◽  
Inverse Gamma ◽  
Major Gene Effect

AbstractSegregation analyses were applied to data from an experimental sheep flock to investigate the presence of a major gene affecting litter size. The data set contained 14 years of litter size data, with up to five parities per ewe, from Cheviot sheep carrying the putative Thoka fecundity gene from Icelandic sheep. Segregation analyses were performed using a Markov chain Monte Carlo method implemented using Gibbs sampling. Uniform priors were initially used for estimating variance components, the gene effect and fixed effects in the data. Genotypes in the base generation were assumed known based on the use of the imported Icelandic donor semen from the founder rams. The use of alternative priors (naïve and inverse-gamma distributions) for the variance components did not significantly affect the results, demonstrating the data to be sufficiently powerful for the analyses used. Segregation analyses detected a major gene for litter size in the Thoka Cheviot flock increasing litter size by 0·70 lambs per ewe lambing for a single copy of the gene. When the analysis was repeated without fixing the genotypes in the base population, the analyses predicted a different genotype than that previously used for one of the founder rams and suggested the major gene to be segregating in the Cheviot founder animals prior to the introduction of the Thoka rams. A liability threshold analysis was also applied to the data. As identified in other studies, the threshold analysis overestimated the heritability, but the estimated major gene effect was not significantly different from other analyses. The results confirm the segregation of the Thoka gene in a Cheviot flock and highlight the statistical method as a useful tool for identifying carrier animals to be used for future matings.

Periodic catatonia: A schizophrenic subtype with major gene effect and anticipation

1995 ◽  
Vol 245 (3) ◽  
pp. 135-141 ◽  
Author(s):  
G. Stöber ◽  
E. Franzek ◽  
K. P. Lesch ◽  
H. Beckmann
Keyword(s):  
Major Gene ◽  
Gene Effect ◽  
Major Gene Effect ◽  
Periodic Catatonia

scholarly journals Molecular Dissection of a Major Gene Effect on a Quantitative Trait: The Level of Alcohol Dehydrogenase Expression in Drosophila melanogaster

Genetics ◽  
1996 ◽  
Vol 144 (4) ◽  
pp. 1559-1564 ◽  
Author(s):  
Lynn F Stam ◽  
Cathy C Laurie
Keyword(s):  
Drosophila Melanogaster ◽  
Alcohol Dehydrogenase ◽  
Quantitative Trait ◽  
Molecular Mapping ◽  
Major Gene ◽  
Isolated Populations ◽  
Gene Effects ◽  
Gene Effect ◽  
Major Gene Effect ◽  
The Individual

A molecular mapping experiment shows that a major gene effect on a quantitative trait, the level of alcohol dehydrogenase expression in Drosophila melanogaster, is due to multiple polymorphisms within the Adh gene. These polymorphisms are located in an intron, the coding sequence, and the 3′ untranslated region. Because of nonrandom associations among polymorphisms at different sites, the individual effects combine (in some cases epistatically) to produce “superalleles” with large effect. These results have implications for the interpretation of major gene effects detected by quantitative trait locus mapping methods. They show that large effects due to a single locus may be due to multiple associated polymorphisms (or sequential fixations in isolated populations) rather than individual mutations of large effect.

scholarly journals The Cambridge sheep — its exploitation for increased efficiency of lamb production

1988 ◽  
Vol 60 (6) ◽  
pp. 585-590
Author(s):  
J. B. Owen ◽  
I. AP Dewi
Keyword(s):  
Litter Size ◽  
Large Range ◽  
Major Gene ◽  
Ovulation Rate ◽  
Gene Effect ◽  
Generation Interval ◽  
Major Gene Effect ◽  
Feed Utilisation ◽  
Relationship Of ◽  
The Relationship

The Cambridge breed has been developed since 1964, based on a foundation group of 54 ewes representing 11 breeds mated initially to seven Finnsheep rams. Data presented show that a high litter size(LS) has been established (mean 2.8 in 3 year old ewes) by a policy of selection coupled with minimising generation interval. Observations on ovulation rate (OR)show a large range (1—13) and are consistent with an hypothesis that OR is influenced by a major gene effect superimposed on a basal level of about 2.5 ova. The gene appears to increase ovulation by about two ova per copy and to have a frequency approaching 0.3 in the Bangor University flock. Data on the relationship of LS at birth and of lambs weaned per ewe are presented which indicate that under ideal conditions the optima for OR and LS at birth cannot exceed 5 and 3.5 respectively for mature ewes. The practical utilisation of the breed as a dam-line sire of crossbred ewes show that the Cambridge crossbreds are more precocious, more prolific, have slower growing lambs with carcasses of similar quality to the corresponding Border Leicester crosses. Overall superiority inefficiency of feed utilisation is about 20 %. Methods of genotyping sheep and utilising the major gene in practice are discussed.

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