Strong gender differences in reproductive success variance, and the times to the most recent common ancestors

Abstract

The Time To the Most Recent Common Ancestor (TMRCA) based on human mitochondrial DNA (mtDNA) is estimated to be twice that based on the non-recombining part of the Y chromosome (NRY). These TMRCAs have special demographic implications because mtDNA is transmitted only from mother to child, while NRY is passed along from father to son. Therefore, the former locus reflects female history, and the latter, male history. To investigate what caused the two-to-one female-male TMRCA ratio r F/M = T F /T M in humans, we develop a forward-looking agentbased model (ABM) with overlapping generations. Our ABM simulates agents with individual life cycles, including life events such as reaching maturity or menopause. We implemented two main mating systems: polygynandry and polygyny with different degrees in between. In each mating system, the male population can be either homogeneous or heterogeneous. In the latter case, some males are 'alphas' and others are 'betas', which reflects the extent to which they are favored by female mates. A heterogeneous male population implies a competition among males with the purpose of signaling as alpha males. The introduction of a heterogeneous male population is found to reduce by a factor 2 the probability of finding equal female and male TMRCAs and shifts the distribution of r F/M to higher values. In order to account for the empirical observation of the factor 2, a high level of heterogeneity in the male population is needed: less than half the males can be alphas and betas can have at most half the fitness of alphas for the TMRCA ratio to depart significantly from 1. In addition, we find that, in the modes that maximize the probability of having 1.5 < r F/M < 2.5, the present generation has 1.4 times as many female as male ancestors. We also tested the effect of sex-biased migration and sex-specific death rates and found that these are unlikely to explain alone the sex-biased TM-RCA ratio observed in humans. Our results support the view that we are descended from males who were successful in a highly competitive context, while females were facing a much smaller female-female competition.

The caloric restriction fallacy, rodent diet aids and the tumor suppression theory of aging

“…Reproductive success is often best in experienced, veteran breeding pairs that have mastered a set of key skills crucial for survival and raising offspring (Angelier et al, 2007), and aging is often a primary natural limit on reproduction in these successful individuals (Bouwhuis et al, 2012;Nussey et al, 2013;Reed et al, 2008;Weimerskirch, 1992). Reproductive success in larger and/or long-lived species appears to be skewed towards a few highly productive individuals not only in birds, but also terrestrial animals such as seals(Le Boeuf et al, 2019) and humans (Favre and Sornette, 2012), and these few highly successful individuals disproportionally profits from longer lifespans.…”

“…Furthermore, once humans survived childhood, their mortality was remarkably low, and significantly lower than that of closely related primates (Finch, 2010;Gurven and Kaplan, 2007). After reaching puberty, prehistoric humans enter a phase of low mortality, whose overall reproductive payoff probably depended significantly on the length of this period of adulthood marked by health, high performance and low mortality, especially in males (Favre and Sornette, 2012). A quantitative understanding of the prehistoric relative evolutionary value of preventing death at different ages is lacking, but it is not unreasonable to conclude that malignancy was an important age-related source of mortality at the upper end of human reproductive activity, the edge at which the reproductive value of additional health span drops below the cost associated with achieving it, and age-related mortality (Supplementary Figure 2) starts to become significant.…”

Uncovering predictability of individual and team success: Significant Hot Hand Effect in International Cricket

“…Figure 2 presents the example of the career of Sachin Tendulkar, who has the highest sum of performances in both formats of the game. Top panels show the performance time 𝐻𝐻(𝑡𝑡) as a function of t, which is the index of the 𝑡𝑡 𝑡𝑡ℎ attempt, as defined in equation (1), for two international cricketing formats, ODI and Test. Bottom panels show the scores 𝑆𝑆 𝑗𝑗 (𝑡𝑡) as a function of 𝑡𝑡, which indexed the 𝑡𝑡 𝑡𝑡ℎ attempt, for the same two international cricketing formats, ODI and Test.…”

“…The study of what bring success or failure in battles and wars, in politics, in business, in sports, even in our personal lives, has a very long history, being part of the DNA of human evolution that has tended to promote the genes of the "successful ones" (1). The 'science of success' has received a boost in recent years with the growing availability of large datasets describing individual's careers from which much can be learned and importantly predicted (2)(3)(4)(5)(6)(7)(8)(9)(10).…”

Utility Rate Equations of Group Population Dynamics in Biological and Social Systems

“…While the classical economic approach often defines the utility of an agent as the present value of future consumption, inter-generational extensions include bequest and the consumption of future generations. It is often argued that one of the most important measure of success is the passing of genes to future generation [69], [70], so that utility, as a measure of happiness, and fitness, as a measure of success, become entangled concepts. We prefer to use the term utility, keeping in mind applications to both biological as well as social systems.…”