Grandmothering life histories and human pair bonding.

The evolution of distinctively human life history and social organization is generally attributed to paternal provisioning based on pair bonds. Here we develop an alternative argument that connects the evolution of human pair bonds to the male-biased mating sex ratios that accompanied the evolution of human life history. We simulate an agent-based model of the grandmother hypothesis, compare simulated sex ratios to data on great apes and human hunter-gatherers, and note associations between a preponderance of males and mate guarding across taxa.

Age-related decline in ovarian follicle stocks differ between chimpanzees (Pan troglodytes) and humans.

Similarity in oldest parturitions in humans and great apes suggests that we maintain ancestral rates of ovarian aging. Consistent with that hypothesis, previous counts of primordial follicles in postmortem ovarian sections from chimpanzees (Pan troglodytes) showed follicle stock decline at the same rate that human stocks decline across the same ages. Here, we correct that finding with a chimpanzee sample more than three times larger than the previous one, which also allows comparison into older ages.

Grandmothering drives the evolution of longevity in a probabilistic model.

We present a mathematical model based on the Grandmother Hypothesis to simulate how human post-menopausal longevity could have evolved as ancestral grandmothers began to assist the reproductive success of younger females by provisioning grandchildren. Grandmothers׳ help would allow mothers to give birth to subsequent offspring sooner without risking the survival of existing offspring. Our model is an agent-based model (ABM), in which the population evolves according to probabilistic rules governing interactions among individuals.

Blood cell telomere lengths and shortening rates of chimpanzee and human females.

Objectives: Slower rates of aging distinguish humans from our nearest living cousins. Chimpanzees rarely survive their forties while large fractions of women are postmenopausal even in high-mortality hunter-gatherer populations. Cellular and molecular mechanisms for these somatic aging differences remain to be identified, though telomeres might play a role.

Grandmothers and the evolution of human longevity: a review of findings and future directions.

Women and female great apes both continue giving birth into their forties, but not beyond. However humans live much longer than other apes do. Even in hunting and gathering societies, where the mortality rate is high, adult life spans average twice those of chimpanzees, which become decrepit during their fertile years and rarely survive them.

Brief communication: Adrenal androgens and aging: Female chimpanzees (Pan troglodytes) compared with women.

Ovarian cycling continues to similar ages in women and chimpanzees yet our nearest living cousins become decrepit during their fertile years and rarely outlive them. Given the importance of estrogen in maintaining physiological systems aside from fertility, similar ovarian aging in humans and chimpanzees combined with somatic aging differences indicates an important role for nonovarian estrogen. Consistent with this framework, researchers have nominated the adrenal androgen dehydroepiandrosterone (DHEA) and its sulfate (DHEAS), which can be peripherally converted to estrogen, as a biomarker of aging in humans and other primates.

Increased longevity evolves from grandmothering.

Postmenopausal longevity may have evolved in our lineage when ancestral grandmothers subsidized their daughters' fertility by provisioning grandchildren, but the verbal hypothesis has lacked mathematical support until now. Here, we present a formal simulation in which life spans similar to those of modern chimpanzees lengthen into the modern human range as a consequence of grandmother effects. Greater longevity raises the chance of living through the fertile years but is opposed by costs that differ for the sexes.

Parental attitudes, beliefs, and perceptions about genetic testing for FAP and colorectal cancer surveillance in minors.

Familial adenomatous polyposis (FAP) is the second most common hereditary colorectal cancer syndrome and confers a nearly 100% lifetime risk of developing colorectal cancer. Understanding factors that facilitate and inhibit genetic testing and cancer surveillance in children who are members of families affected by FAP will better equip clinicians to clarify misunderstandings and facilitate appropriate care. The aims of this study were to examine parental attitudes and beliefs regarding endoscopic surveillance and genetic testing in minors at risk for developing FAP.

Religiosity, spirituality, and psychological distress in African-Americans at risk for having a hereditary cancer predisposing gene mutation.

Elevated psychological distress has been observed among people at increased risk for familial cancer. Researchers consider religiosity and spirituality (RS) to be positive coping mechanisms associated with reduced psychological distress. Relatively little is known about the impact of RS on genomic health issues.