Genetic Causes of Joint Laxity

2008 ◽  
Vol 41 (7) ◽  
pp. 19
Author(s):  
HOWARD P. LEVY
Keyword(s):  
1997 ◽  
Vol 10 (02) ◽  
pp. 69-74 ◽  
Author(s):  
G. K. Smith ◽  
M. G. Conzemius ◽  
H. M. Saunders ◽  
C. M. Hill ◽  
T. P. Gregor ◽  
...  

SummaryA few investigations in the 1960’s were performed to document the effect of exogenous oestrogens on development of hip dysplasia. These projects concluded that oestrogen administration caused a significant increase in hip dysplasia. Additionally, the Orthopaedic Foundation for Animals (OFA) has recommended that bitches should not have hip evaluation for certification during oestrus, due to the possibility of increased coxofemoral joint laxity. The purpose of this project was to determine if physiological fluctuations of oestrogen and progesterone throughout the oestrus cycle significantly affected coxofemoral joint laxity. Nine bitches were evaluated through a single oestrus cycle. Although significant fluctuations of oestrogen and progesterone occurred throughout the phases of the oestrus cycle, neither statistically nor clinically significant changes in coxofemoral joint laxity were documented.A prospective study documented the effect of fluctuations of hormone levels throughout the oestrus cycle on coxofemoral joint laxity in nine dogs. Although oestrogen and progesterone levels changed significantly throughout the oestrus cycle, neither statistically nor clinically significant changes in hip laxity were observed.


2019 ◽  
Author(s):  
Antoni Riera-Escamilla ◽  
Andrea Enguita-Marruedo ◽  
Daniel Moreno-Mendoza ◽  
Chiara Chianese ◽  
Eduard Ruiz-Castane ◽  
...  

Genetics ◽  
1998 ◽  
Vol 148 (3) ◽  
pp. 1333-1340 ◽  
Author(s):  
Hong-Wen Deng ◽  
Yun-Xin Fu

AbstractThe past decades have witnessed extensive efforts to correlate fitness traits with genomic heterozygosity. While positive correlations are revealed in most of the organisms studied, results of no/negative correlations are not uncommon. There has been little effort to reveal the genetic causes of these negative correlations. The positive correlations are regarded either as evidence for functional overdominance in large, randomly mating populations at equilibrium, or the results of populations at disequilibrium under dominance. More often, the positive correlations are viewed as a phenomenon of heterosis, so that it cannot possibly occur under within-locus additive allelic effects. Here we give exact genetic conditions that give rise to positive and negative correlations in populations at Hardy-Weinberg and linkage equilibria, thus offering a genetic explanation for the observed negative correlations. Our results demonstrate that the above interpretations concerning the positive correlations are not complete or even necessary. Such a positive correlation can result under dominance and potentially under additivity, even in populations where associated overdominance due to linked alleles at different loci is not significant. Additionally, negative correlations and heterosis can co-occur in a single population. Although our emphasis is on equilibrium populations and for biallelic genetic systems, the basic conclusions are generalized to non-equilibrium populations and for multi-allelic situations.


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