scholarly journals Do Somatic Cells Really Sacrifice Themselves? Why an Appeal to Coercion May be a Helpful Strategy in Explaining the Evolution of Multicellularity

2021 ◽  
Author(s):  
Adrian Stencel ◽  
Javier Suárez
Keyword(s):  
Present Article ◽  
Evolutionary Biology ◽  
Genetic Relatedness ◽  
Inclusive Fitness ◽  
Somatic Cells ◽  
Next Generation ◽  
Inclusive Fitness Theory ◽  
Germline Cells ◽  
Multicellular Organisms

AbstractAn understanding of the factors behind the evolution of multicellularity is one of today’s frontiers in evolutionary biology. This is because multicellular organisms are made of one subset of cells with the capacity to transmit genes to the next generation (germline cells) and another subset responsible for maintaining the functionality of the organism, but incapable of transmitting genes to the next generation (somatic cells). The question arises: why do somatic cells sacrifice their lives for the sake of germline cells? How is germ/soma separation maintained? One conventional answer refers to inclusive fitness theory, according to which somatic cells sacrifice themselves altruistically, because in so doing they enhance the transmission of their genes by virtue of their genetic relatedness to germline cells. In the present article we will argue that this explanation ignores the key role of policing mechanisms in maintaining the germ/soma divide. Based on the pervasiveness of the latter, we argue that the role of altruistic mechanisms in the evolution of multicellularity is limited and that our understanding of this evolution must be enriched through the consideration of coercion mechanisms.

scholarly journals Male relatedness and familiarity are required to modulate male-induced harm to females in Drosophila

2017 ◽  
Vol 284 (1860) ◽  
pp. 20170441 ◽  
Author(s):  
Sally Le Page ◽  
Irem Sepil ◽  
Ewan Flintham ◽  
Tommaso Pizzari ◽  
Pau Carazo ◽  
...  
Keyword(s):  
Potential Role ◽  
Genetic Relatedness ◽  
Inclusive Fitness ◽  
Kin Recognition ◽  
Female Reproduction ◽  
Fitness Effects ◽  
Inclusive Fitness Theory ◽  
Indirect Fitness ◽  
Female Lifespan

Males compete over mating and fertilization, and often harm females in the process. Inclusive fitness theory predicts that increasing relatedness within groups of males may relax competition and discourage male harm of females as males gain indirect benefits. Recent studies in Drosophila melanogaster are consistent with these predictions, and have found that within-group male relatedness increases female fitness, though others have found no effects. Importantly, these studies did not fully disentangle male genetic relatedness from larval familiarity, so the extent to which modulation of harm to females is explained by male familiarity remains unclear. Here we performed a fully factorial design, isolating the effects of male relatedness and larval familiarity on female harm. While we found no differences in male courtship or aggression, there was a significant interaction between male genetic relatedness and familiarity on female reproduction and survival. Relatedness among males increased female lifespan, reproductive lifespan and overall reproductive success, but only when males were familiar. By showing that both male relatedness and larval familiarity are required to modulate female harm, these findings reconcile previous studies, shedding light on the potential role of indirect fitness effects on sexual conflict and the mechanisms underpinning kin recognition in fly populations.

scholarly journals Testing the Kundera Hypothesis: Does Every Woman (But Not Every Man) Prefer Her Child to Her Mate?

2018 ◽  
Vol 16 (4) ◽  
pp. 147470491880886
Author(s):  
Carlos Hernández Blasi ◽  
Laura Mondéjar
Keyword(s):  
College Students ◽  
Inclusive Fitness ◽  
Milan Kundera ◽  
Men And Women ◽  
Car Crash ◽  
Inclusive Fitness Theory ◽  
Role Of Women

The context of a famous novel by Milan Kundera ( Immortality) suggests that when faced with a life-or-death situation, every woman would prefer to save her child than her husband, left hanging whether every man would do the same. We labeled this as the Kundera hypothesis, and the purpose of this study was to test it empirically as we believe it raises a thought-provoking question in evolutionary terms. Specifically, 197 college students (92 women) were presented a questionnaire where they had to make different decisions about four dilemmas about who to save (their mate or their offspring) in two hypothetical life-or-death situations: a home fire and a car crash. These dilemmas involved two different mate ages (a 25- or a 40-year-old mate) and two offspring ages (1- or a 6-year-old child). For comparative purposes, we also included complementary life-or-death dilemmas on both a sibling and an offspring, and a sibling and a cousin. The results generally supported the Kundera hypothesis: Although the majority of men and women made the decision to save their offspring instead of their mate, about 18% of men on average (unlike the 5% of women) consistently decided to save their mate across the four dilemmas in the two life-or-death situations. These data were interpreted with reference to Hamilton’s inclusive fitness theory, the preferential role of women as kin keepers, and the evolution of altruism toward friends and mates.

scholarly journals The validity and value of inclusive fitness theory

2011 ◽  
Vol 278 (1723) ◽  
pp. 3313-3320 ◽  
Author(s):  
Andrew F. G. Bourke
Keyword(s):  
Kin Selection ◽  
Evolutionary Biology ◽  
Social Evolution ◽  
Inclusive Fitness ◽  
Evidence Base ◽  
Alternative Theory ◽  
Selection Theory ◽  
Inclusive Fitness Theory ◽  
Evolution Of Eusociality ◽  
Natural Selection Theory

Social evolution is a central topic in evolutionary biology, with the evolution of eusociality (societies with altruistic, non-reproductive helpers) representing a long-standing evolutionary conundrum. Recent critiques have questioned the validity of the leading theory for explaining social evolution and eusociality, namely inclusive fitness (kin selection) theory. I review recent and past literature to argue that these critiques do not succeed. Inclusive fitness theory has added fundamental insights to natural selection theory. These are the realization that selection on a gene for social behaviour depends on its effects on co-bearers, the explanation of social behaviours as unalike as altruism and selfishness using the same underlying parameters, and the explanation of within-group conflict in terms of non-coinciding inclusive fitness optima. A proposed alternative theory for eusocial evolution assumes mistakenly that workers' interests are subordinate to the queen's, contains no new elements and fails to make novel predictions. The haplodiploidy hypothesis has yet to be rigorously tested and positive relatedness within diploid eusocial societies supports inclusive fitness theory. The theory has made unique, falsifiable predictions that have been confirmed, and its evidence base is extensive and robust. Hence, inclusive fitness theory deserves to keep its position as the leading theory for social evolution.

scholarly journals Do Relatives With Greater Reproductive Potential Get Help First?: A Test of the Inclusive Fitness Explanation of Kin Altruism

2019 ◽  
Vol 17 (3) ◽  
pp. 147470491986709
Author(s):  
Jordan Schriver ◽  
W.Q. Elaine Perunovic ◽  
Kyle Brymer ◽  
Timothy Hachey
Keyword(s):  
Genetic Relatedness ◽  
Inclusive Fitness ◽  
Reproductive Potential ◽  
Causal Effects ◽  
Emotional Closeness ◽  
Child Study ◽  
Inclusive Fitness Theory

According to inclusive fitness theory, people are more willing to help those they are genetically related to because relatives share a kin altruism gene and are able to pass it along. We tested this theory by examining the effect of reproductive potential on altruism. Participants read hypothetical scenarios and chose between cousins (Studies 1 and 2) and cousins and friends (Study 3) to help with mundane chores or a life-or-death rescue. In life-or-death situations, participants were more willing to help a cousin preparing to conceive rather than adopt a child (Study 1) and a cousin with high rather than low chance of reproducing (Studies 2 and 3). Patterns in the mundane condition were less consistent. Emotional closeness also contributed to helping intentions (Studies 1 and 2). By experimentally manipulating reproductive potential while controlling for genetic relatedness and emotional closeness, we provide a demonstration of the direct causal effects of reproductive potential on helping intentions, supporting the inclusive fitness explanation of kin altruism.

scholarly journals Intercellular competition and the inevitability of multicellular aging

2017 ◽  
Vol 114 (49) ◽  
pp. 12982-12987 ◽  
Author(s):  
Paul Nelson ◽  
Joanna Masel
Keyword(s):  
Somatic Cells ◽  
Multicellular Organism ◽  
Double Bind ◽  
Antagonistic Pleiotropy ◽  
Full Understanding ◽  
Effects Of Aging ◽  
Multicellular Organisms ◽  
Somatic Selection

Current theories attribute aging to a failure of selection, due to either pleiotropic constraints or declining strength of selection after the onset of reproduction. These theories implicitly leave open the possibility that if senescence-causing alleles could be identified, or if antagonistic pleiotropy could be broken, the effects of aging might be ameliorated or delayed indefinitely. These theories are built on models of selection between multicellular organisms, but a full understanding of aging also requires examining the role of somatic selection within an organism. Selection between somatic cells (i.e., intercellular competition) can delay aging by purging nonfunctioning cells. However, the fitness of a multicellular organism depends not just on how functional its individual cells are but also on how well cells work together. While intercellular competition weeds out nonfunctional cells, it may also select for cells that do not cooperate. Thus, intercellular competition creates an inescapable double bind that makes aging inevitable in multicellular organisms.

scholarly journals Multicellularity makes somatic differentiation evolutionarily stable

2014 ◽  
Author(s):  
Mary Elizabeth Wahl ◽  
Andrew Wood Murray
Keyword(s):  
Saccharomyces Cerevisiae ◽  
Germ Cells ◽  
Budding Yeast ◽  
Somatic Cells ◽  
Evolutionary Stability ◽  
Next Generation ◽  
Cell Lineages ◽  
Multicellular Organisms ◽  
Evolutionarily Stable

Many multicellular organisms produce two cell lineages: germ cells, whose descendants form the next generation, and somatic cells which support, protect, and disperse the germ cells. This distinction has evolved independently in dozens of multicellular taxa but is absent in unicellular species. We propose that unicellular, soma-producing populations are intrinsically susceptible to invasion by non-differentiating mutants which ultimately eradicate the differentiating lineage. We argue that multicellularity can prevent the victory of such mutants. To test this hypothesis, we engineer strains of the budding yeastSaccharomyces cerevisiaethat differ only in the presence or absence of multicellularity and somatic differentiation, permitting direct comparisons between organisms with different lifestyles. We find that non-differentiating mutants overtake unicellular populations but are outcompeted by multicellular differentiating strains, suggesting that multicellularity confers evolutionary stability to somatic differentiation.

The Biological Nature of the State

1983 ◽  
Vol 35 (2) ◽  
pp. 161-193 ◽  
Author(s):  
R. D. Masters
Keyword(s):  
Evolutionary Biology ◽  
Choice Theory ◽  
Inclusive Fitness ◽  
Cost Benefit ◽  
The State ◽  
Scientific Terminology ◽  
Inclusive Fitness Theory ◽  
The Commons ◽  
Law And Justice ◽  
Rational Actor Models

The origin of the state, long at the center of political science, can be greatly illuminated by the contemporary approach in evolutionary biology known as “inclusive fitness theory.” Natural selection is now analyzed using cost-benefit models akin to rational actor models in economics, game theory, and collective choice theory. The utility of integrating these approaches is illustrated by using the Prisoner's Dilemma and the Tragedy of the Commons to outline a general model for the evolution of political and legal institutions. This perspective also shows how traditional political philosophers explored “archetypical” problems that are easily translated into scientific terminology. It is thus possible to link biology to the study of human behavior in a nonreductionist manner, thereby generating new empirical hypotheses concerning the environmental correlates of social norms. Ultimately, such a unification of the natural and social sciences points to a return to the classical view that law and justice are not matters of pure convention, but rather are grounded on what is right “according to nature.”

scholarly journals The extended evolutionary synthesis and the role of soft inheritance in evolution

2012 ◽  
Vol 279 (1740) ◽  
pp. 2913-2921 ◽  
Author(s):  
Thomas E. Dickins ◽  
Qazi Rahman
Keyword(s):  
Cultural Transmission ◽  
Evolutionary Biology ◽  
Inclusive Fitness ◽  
Average Lifetime ◽  
Biological Organization ◽  
Extended Evolutionary Synthesis ◽  
The Core ◽  
Made In ◽  
Key Questions

In recent years, a number of researchers have advocated extending the modern synthesis in evolutionary biology. One of the core arguments made in favour of an extension comes from work on soft inheritance systems, including transgenerational epigenetic effects, cultural transmission and niche construction. In this study, we outline this claim and then take issue with it. We argue that the focus on soft inheritance has led to a conflation of proximate and ultimate causation, which has in turn obscured key questions about biological organization and calibration across the life span to maximize average lifetime inclusive fitness. We illustrate this by presenting hypotheses that we believe incorporate the core phenomena of soft inheritance and will aid in understanding them.

scholarly journals Evolution of eusociality: the advantage of assured fitness returns

1990 ◽  
Vol 329 (1252) ◽  
pp. 17-25 ◽  
Keyword(s):  
Evolutionary Biology ◽  
Genetic Relatedness ◽  
Inclusive Fitness ◽  
Laboratory Data ◽  
Ropalidia Marginata ◽  
Primitively Eusocial Wasp ◽  
Entire Duration ◽  
Eusocial Wasp ◽  
Worker Brood ◽  
Worker Castes

Delineation of the selective pressures responsible for the evolution ol sterile worker castes found in social insect colonies remains a major unsolved problem in evolutionary biology. There has therefore been a great deal of interest in suggesting ways by which the inclusive fitness of sterile workers can potentially be larger than those of solitary nest-builders. Queller’s (1989) head-start hypothesis ( Proc. natn. Acad. Sci. U.S.A. 86, 3224) suggests that workers may gain relatively more inclusive fitness because they have access to young of various ages which can be quickly brought to the age of independence, whereas a solitary foundress has to survive for the entire duration of the development of her brood. I argue here that Queller's quantitative analysis is incorrect because it gives an unfair advantage to workers, either by giving full credit of rearing an offspring to a worker who only cared for it for a short while or, by assuming that a worker can do much more work per unit time than a solitary foundress. I show, however, that workers do indeed have an advantage over solitary foundresses because they have assured fitness returns, even if in small amounts, for short periods of work. This results from a different reckoning from that used by Queller and gives a more moderate advantage, arising essentially from saving the wasted effort that occurs when lone foundress nests fail. Using field and laboratory data on the primitively eusocial wasp Ropalidia marginata , and re-analysing data on the four species of polistine wasps used by Queller, I show that such an ‘assured fitness returns' model provides a selective pressure for the evolution of worker behaviour which is at least about as strong as that of haplodiploidy, but free from such requirements of the latter as high levels of worker-brood genetic relatedness and ability of workers to manipulate brood sex ratios.

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