New Estimates of Intergenerational Time Intervals for the Calculation of Age and Origins of Mutations

Abstract

Intergenerational time intervals are frequently used in human population-genetics studies concerned with the ages and origins of mutations. In most cases, mean intervals of 20 or 25 years are used, regardless of the demographic characteristics of the population under study. Although these characteristics may vary from prehistoric to historical times, we suggest that this value is probably too low, and that the ages of some mutations may have been underestimated. Analyses were performed by using the BALSAC Population Register (Quebec, Canada), from which several intergenerational comparisons can be made. Family reconstitutions were used to measure interval lengths and variations in descending lineages. Various parameters were considered, such as spouse age at marriage, parental age, and reproduction levels. Mother-child and father-child intervals were compared. Intergenerational male and female intervals were also analyzed in 100 extended ascending genealogies. Results showed that a mean value of 30 years is a better estimate of intergenerational intervals than 20 or 25 years. As marked differences between male and female interval length were observed, specific values are proposed for mtDNA, autosomal, X-chromosomal, and Y-chromosomal loci. The applicability of these results for age estimates of mutations is discussed.

The western Swedish BRCA1 founder mutation 3171ins5; a 3.7 cM conserved haplotype of today is a reminiscence of a 1500-year-old mutation

“…27 This number of generation is in line with, and sometimes somewhat greater than, other studies, e.g. from founder mutation age analyses, e.g.…”

The Indian origin of paternal haplogroup R1a1* substantiates the autochthonous origin of Brahmins and the caste system

“…We also applied g¼32 in calculating the age estimates, keeping in mind the recent compelling evidences that the age of the male generation in modern times is closer to 32 or 35 years. 49,50 Origin of paternal haplogroup R1a1* S Sharma et al Table 1 Y-haplogroups percentage distribution in studied regional population groups of India Origin of paternal haplogroup R1a1* S Sharma et al…”

Relative fitness of carriers of the mitochondrial DNA mutation 3243A > G

“…Interestingly, we found that the generation time was not different between the mutation carriers and the general population and it was also similar to that estimated from a historical population. 13 It is also possible that morbidity and mortality from the mutation have changed. Diabetes mellitus, a common phenotype associated with the 3243A > G mutation, may have proved fatal in earlier times but is now treatable.…”