Human aging and somatic point mutations in mtDNA: a comparative study of generational differences (grandparents and grandchildren)

The accumulation of somatic mutations in mtDNA is correlated with aging. In this work, we sought to identify somatic mutations in the HVS-1 region (D-loop) of mtDNA that might be associated with aging. For this, we compared 31 grandmothers (mean age: 63 ± 2.3 years) and their 62 grandchildren (mean age: 15 ± 4.1 years), the offspring of their daughters. Direct DNA sequencing showed that mutations absent in the grandchildren were detected in a presumably homoplasmic state in three grandmothers and in a heteroplasmic state in an additional 13 grandmothers; no mutations were detected in the remaining 15 grandmothers. However, cloning followed by DNA sequencing in 12 grandmothers confirmed homoplasia in only one of the three mutations previously considered to be homoplasmic and did not confirm heteroplasmy in three out of nine grandmothers found to be heteroplasmic by direct sequencing. Thus, of 12 grandmothers in whom mtDNA was analyzed by cloning, eight were heteroplasmic for mutations not detected in their grandchildren. In this study, the use of genetically related subjects allowed us to demonstrate the occurrence of age-related (> 60 years old) mutations (homoplasia and heteroplasmy). It is possible that both of these situations (homoplasia and heteroplasmy) were a long-term consequence of mitochondrial oxidative phosphorylation that can lead to the accumulation of mtDNA mutations throughout life.

Relative age effect on the reaction time of soccer players under 13 years old

O efeito da idade relativa, que consiste na vantagem obtida pelo atleta nascido mais próximo ao início do ano de seleção, tem se mostrado uma variável importante para o processo de seleção de esportistas. Este estudo objetivou avaliar a influência da época de nascimento no tempo de reação de escolha de futebolistas presentes nas categorias de base (sub 13) de clubes profissionais futebol. Participaram 76 atletas com idade de 13,36 ± 0,45 anos. Os voluntários foram submetidos ao teste do TRE, e os resultados categorizados conforme o semestre de nascimento (S1 ou S2). Foi empregado o teste t para a comparação entre grupos, e análise de Correlação de Pearson para verificar a existência de associações entre as variáveis. Os resultados não indicaram diferenças entre os grupos no tempo de reação (r = 0,033 e p = 0,772) e no tempo de movimento (r = 0,0073 e p = 0,530). Concluiu-se que para essa população, a época de nascimento não influencia no desempenho dessa capacidade.