Heterozygosity testing and multiplex DNA panel screening as a potential tool to monitor health and inbreeding in a small, closed dog population

Background

Selective breeding in populations with a limited effective population size may result in a loss of genetic diversity, which can cause an increased concentration of specific disease liability genes. The Dutch Shepherd Dog (DSD) in the Netherlands is an example of such a breed with a small effective population.

Objective

To evaluate the measurement of genetic diversity and multiplex DNA panel screening for implementation in a breeding strategy for the Dutch Shepherd Dog (DSD) and to investigate the clinical relevance of potentially identified mutations in the multiplex DNA panel screening.

Results

Genome-wide SNP testing showed genetic isolation and reduced genetic diversity within coat variety subgroups of the DSD. Panel screening identified a Von Willebrand's Disease type I mutation. Although decreased Von Willebrand's Factor proteins were significantly lower in DSDs carrying the VWD-I allele compared to the wildtype, clinical follow-up did not show a significant association between the clinical phenotype and VWD-I genotype.

Conclusions

Genetic relationship measurement within a breed population may be a useful tool to enable breeding strategies to conserve genetic diversity. Results from a disease panel screening need to be evaluated for clinical relevance before breed selection restrictions can be considered.

A novel KRT71 variant in curly-coated dogs

Curly fur is a common phenotype in many dog breeds, known to result from a missense variant (c.451C>T) in exon 2 of the keratin 71 (KRT71) gene. During screening for this variant across various breeds, we found that Curly Coated Retrievers (CCRs) fixed with the trait did not carry the known variant. By analysis of whole-genome sequencing data of one CCR we identified a novel genetic cause for curly fur. We found a novel structural variant in exon 7 of the KRT71 gene (c.1266_1273delinsACA) that was predicted to result in a frameshift and stop loss, therefore significantly affecting the structure of the protein, if translated. The variant was also found at lower frequencies in five other breeds, including Lagotto Romagnolo, Bichon Frise, Spanish Water Dog, Chesapeake Bay Retriever and Irish Terrier. One curly-coated Lagotto carried neither of the two KRT71 variants. These results identify a second variant for curly coat in KRT71 and suggest the existence of additional alleles. This study enables the development of an additional KRT71 gene test for breeders to understand and manage coat types.

Findings from the preparticipation athletic examination and athletic injuries

This study investigated the relationships between the findings from a standardized preparticipation athletic examination, the sport played, and athletic injuries requiring treatment by a physician and/or requiring the athlete to miss one or more games. Of public high school students receiving a preparticipation athletic examination during the 1989-1990 academic year, 674 (56%) either completed a telephone interview or returned a mailed questionnaire at the end of the academic year. The sample consisted of 408 (60.5%) blacks and 243 (36.1%) whites; 470 (69.7%) of the subjects were males. The subjects ranged in age from 13 to 20 years (mean +/- SD, 16.1 +/- 1.2 years), and participated in at least 10 school sports. Injuries were reported by 29.5% of the athletes. The highest proportion of athletes injured occurred among male football (36.3%), female basketball (33.3%), male baseball (19.4%), male soccer (17.2%), and female track and field (15.8%) participants. Responses by the athletes and their parents on the standardized health history were significantly associated with injuries in several specific areas. Knee injuries were associated with previous knee injuries, knee surgery, and history of injuries requiring medical treatment. Ankle injuries were associated with previous ankle injuries and previous injuries requiring medical treatment. Both arm and other leg injuries were associated with previous fractures. Male athletes with either abnormal knee or ankle findings from the physical examination were more likely to injure the knee or ankle, respectively. However, the sensitivities and positive predictive values of these relationships are weak. These data suggest that the preparticipation athletic examination may not predict certain athletic injuries and that additional prevention efforts for specific body areas of injury are needed in certain sports.

Adolescents' attrition from school-sponsored sports

This study investigated reasons for adolescents' attrition from school-sponsored sports teams and the relationship between attrition and intention to participate in organized and nonorganized sports in the future. Of 674 high school student athletes, 26% dropped off at least one team in 1989-1990, and overall attrition increased to 29.8% when attrition from more than one sport was considered. Attrition was higher among black students, students reporting an athletic injury, those injured playing football, and those sustaining a knee injury. Injury was cited as the most frequent reason for attrition, followed by being cut from the team, "other reasons," needing to get a job, inconvenient game or practice schedule, and needing more time to study, although the main reason for attrition also varied by sport. When athletes were classified according to externally precipitated attrition, athlete-initiated attrition, or completion of the sports season, no differences were noted in the three groups' intent to engage in organized sports in the future. However, the group with externally precipitated attrition expressed a stronger intent to engage in nonorganized sports in the future than the other two groups.