Correlation of surnames and Y-chromosome in Central-Brazil

In patrilineal societies, surnames and Y-specific haplotypes and haplogroups are expected to be correlated. This characteristic could help defining an initial pool of suspects in forensic genetics analysis. Here we evaluated this correlation in a sample of Central-Brazilian men. Surnames and Y-SNP haplogroup and Y-STR haplotype were analyzed in 55 pairs of Central-Brazilian men sharing surnames (n = 110). Seven haplogroups and thirty-two haplotypes have been observed, none correlated solely to any of the twenty-eight surnames represented here. In this sample, two men with the same surname showed a chance of 0.41 of sharing a Y-specific haplogroup. This chance is higher for surnames of intermediate frequencies, whereas rare surnames show distinct chances as zero and one. Observed results may be over-estimated due to a predominance of a specific haplogroup (P92R7 = 49%) in the sample, what makes it possible for two men with no coancestry to share this haplogroup. Considering STR, only three pairs of men shared haplotypes. The average difference between the haplotypes in each pair was 2.45 mutational steps. This relatively low correlation is due to some historical and cultural peculiarities of the country, what makes it improper for forensic purposes in Brazil.     

Subjective Invulnerability,Optimism Bias and Adjustment in Emerging Adulthood

The relationship between subjective invulnerability and optimism bias in risk appraisal, and their comparative association with indices of risk activity, substance use and college adjustment problems was assessed in a sample of 350 (M _age = 20.17; 73% female; 93% White/European American) emerging adults. Subjective invulnerability was measured with the newly devised adolescent invulnerability scale (AIS). Optimism bias in decision-making was assessed with a standard comparative-conditional risk appraisal task. Results showed that the danger- and psychological invulnerability subscales of the AIS demonstrated strong internal consistency and evidence of predictive validity. Subjective invulnerability and optimism bias were also shown to be empirically distinct constructs with differential ability to predict risk and adjustment. Danger invulnerability and psychological invulnerability were more pervasively associated with risk behavior than was optimism bias; and psychological invulnerability counter-indicated depression, self-esteem and interpersonal problems. Results support recent claims regarding the “two faces” of adolescent invulnerability. Implications for future research are drawn.