@article{SchusterHerdeMazzonietal.2016, author = {Schuster, Andrea C. and Herde, Antje and Mazzoni, Camila J. and Eccard, Jana and Sommer, Simone}, title = {Evidence for selection maintaining MHC diversity in a rodent species despite strong density fluctuations}, series = {Immunogenetics}, volume = {68}, journal = {Immunogenetics}, publisher = {Springer}, address = {New York}, issn = {0093-7711}, doi = {10.1007/s00251-016-0916-z}, pages = {429 -- 437}, year = {2016}, abstract = {Strong spatiotemporal variation in population size often leads to reduced genetic diversity limiting the adaptive potential of individual populations. Key genes of adaptive variation are encoded by the immune genes of the major histocompatibility complex (MHC) playing an essential role in parasite resistance. How MHC variation persists in rodent populations that regularly experience population bottlenecks remains an important topic in evolutionary genetics. We analysed the consequences of strong population fluctuations on MHC class II DRB exon 2 diversity in two distant common vole (Microtus arvalis) populations in three consecutive years using a high-throughput sequencing approach. In 143 individuals, we detected 25 nucleotide alleles translating into 14 unique amino acid MHC alleles belonging to at least three loci. Thus, the overall allelic diversity and amino acid distance among the remaining MHC alleles, used as a surrogate for the range of pathogenic antigens that can be presented to T-cells, are still remarkably high. Both study populations did not show significant population differentiation between years, but significant differences were found between sites. We concluded that selection processes seem to be strong enough to maintain moderate levels of MHC diversity in our study populations outcompeting genetic drift, as the same MHC alleles were conserved between years. Differences in allele frequencies between populations might be the outcome of different local parasite pressures and/or genetic drift. Further understanding of how pathogens vary across space and time will be crucial to further elucidate the mechanisms maintaining MHC diversity in cyclic populations.}, language = {en} } @article{MkaouerHammoudiNassibAmaraetal.2018, author = {Mkaouer, Bessem and Hammoudi-Nassib, Sarra and Amara, Samiha and Chaabene, Helmi}, title = {Evaluating the physical and basic gymnastics skills assessment for International Gymnastics Federation}, series = {Biology of Sport}, volume = {35}, journal = {Biology of Sport}, number = {4}, publisher = {Inst Sport}, address = {Warsaw}, issn = {0860-021X}, doi = {10.5114/biolsport.2018.78059}, pages = {383 -- 392}, year = {2018}, abstract = {This study aimed to determine the specific physical and basic gymnastics skills considered critical in gymnastics talent identification and selection as well as in promoting men's artistic gymnastics performances. Fifty-one boys from a provincial gymnastics team (age 11.03 ± 0.95 years; height 1.33 ± 0.05 m; body mass 30.01 ± 5.53 kg; body mass index [BMI] 16.89 ± 3.93 kg/m²) regularly competing at national level voluntarily participated in this study. Anthropometric measures as well as the men's artistic gymnastics physical test battery (i.e., International Gymnastics Federation [FIG] age group development programme) were used to assess the somatic and physical fitness profile of participants, respectively. The physical characteristics assessed were: muscle strength, flexibility, speed, endurance, and muscle power. Test outcomes were subjected to a principal components analysis to identify the most representative factors. The main findings revealed that power speed, isometric and explosive strength, strength endurance, and dynamic and static flexibility are the most determinant physical fitness aspects of the talent selection process in young male artistic gymnasts. These findings are of utmost importance for talent identification, selection, and development.}, language = {en} }