Princeton/Stanford Working Papers in Classics
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Cousin Marriage & Inbreeding Depression
Evidence of Inbreeding Depression: Saudi Arabia Saudi Intermarriages Have Genetic Costs [Important note from Raymond Hames (your instructor). Cousin marriage in the United States is not as risky compared to cousin marriage in Saudi Arabia and elsewhere where there is a long history of repeated inter-marriage between close kin. Ordinary cousins without a history previous intermarriage are related to one another by 0.0125. However, in societies with a long history of intermarriage, relatedness is much higher. For US marriages a study published in The Journal of Genetic Counseling in 2002 said that the risk of serious genetic defects like spina bifida and cystic fibrosis in the children of first cousins indeed exists but that it is rather small, 1.7 to 2.8 percentage points higher than for children of unrelated parents, who face a 3 to 4 percent risk — or about the equivalent of that in children of women giving birth in their early 40s. The study also said the risk of mortality for children of first cousins was 4.4 percentage points higher.] By Howard Schneider Washington Post Foreign Service Sunday, January 16, 2000; Page A01 RIYADH, Saudi Arabia-In the centuries that this country's tribes have scratched a life from the Arabian Peninsula, the rule of thumb for choosing a marriage partner has been simple: Keep it in the family, a cousin if possible, or at least a tribal kin who could help conserve resources and contribute to the clan's support and defense. But just as that method of matchmaking served a purpose over the generations, providing insurance against a social or financial mismatch, so has it exacted a cost--the spread of genetic disease. -
Inbreeding Depression in Two Populations of Arenaria Uni¯Ora (Caryophyllaceae) with Contrasting Mating Systems
Heredity 86 (2001) 184±194 Received 16 November 1999, accepted 17 October 2000 Inbreeding depression in two populations of Arenaria uni¯ora (Caryophyllaceae) with contrasting mating systems LILA FISHMAN Department of Ecology and Evolutionary Biology, Princeton University, Princeton, NJ 08544 U.S.A. I used parallel family-structured crossing designs to investigate the relative performance of self and outcross progeny in sel®ng and predominantly outcrossing populations of the annual plant Arenaria uni¯ora. The selfer population experienced much lower inbreeding depression (d 0.05 0.02 SE) than the outcrossers (d 0.19 0.02 SE). The negative association between genetic load and sel®ng rate suggests that purgable partially recessive alleles are the primary source of inbreeding depression, as does its late expression in both populations. Inbreeding depression in the selfer population, which naturally consists of highly inbred lines, was used to calculate the mean dominance (h 0.33) and incidence rate (U 0.30) of deleterious mutations. In the outcrosser population, signi®cant variation among individuals in the expression of inbreeding depression may re¯ect lineage-speci®c dierences in inbreeding history or, more probably, random variation in mutational load. The low (0.5) inbreeding depression of outcrossers suggests that the maintenance of a mixed mating system in some A. uni¯ora populations and the evolution of nearly cleistogamous self-pollination in others may re¯ect local pollinator-mediated selection for sel®ng rather than the constant 3:2 genetic advantage invoked by many models. Keywords: Arenaria uni¯ora, genetic load, inbreeding depression, mating system, sel®ng. -
Genetic Inbreeding Depression Load for Morphological Traits and Defects in the Pura Raza Española Horse Julia Poyato‑Bonilla1† , Davinia I
Poyato‑Bonilla et al. Genet Sel Evol (2020) 52:62 https://doi.org/10.1186/s12711‑020‑00582‑2 Genetics Selection Evolution RESEARCH ARTICLE Open Access Genetic inbreeding depression load for morphological traits and defects in the Pura Raza Española horse Julia Poyato‑Bonilla1† , Davinia I. Perdomo‑González1*† , María J. Sánchez‑Guerrero1 , Luis Varona2 , Antonio Molina3 , Joaquim Casellas4 and Mercedes Valera1 Abstract Background: Inbreeding is caused by mating between related individuals and is associated with reduced ftness and performance (inbreeding depression). Several studies have detected heterogeneity in inbreeding depression among founder individuals. Recently, a procedure was developed to predict hidden inbreeding depression load that is associ‑ ated with founders using the Mendelian sampling of non‑founders. The objectives of this study were to: (1) analyse the population structure and general inbreeding, and (2) test this recent approach for predicting hidden inbreeding depression load for four morphological traits and two morphology defects in the Pura Raza Española (PRE) horse breed. Results: The regression coefcients that were calculated between trait performances and inbreeding coefcients demonstrated the existence of inbreeding depression. In total, 58,772,533 partial inbreeding coefcients (Fij) were esti‑ mated for the whole PRE population (328,706 horses). We selected the descendants of horses with a Fij 6.25% that contributed to at least four ofspring and for which morphological traits were measured for the subsequent≥ analysis of inbreeding depression load (639 horses). A pedigree was generated with the last fve generations (5026 animals) used as the reference population (average inbreeding coefcient of 8.39% and average relatedness coefcient of 10.76%). -
Incest Avoidance and Prohibition: Psychobiological and Cultural Factors
Psicologia USP http://dx.doi.org/10.1590/0103-656420160050 287 Evitação e proibição do incesto: fatores psicobiológicos e culturais Francisco Wilson Nogueira Holanda Júnior* Universidade Federal do Rio Grande do Norte, Programa de Pós-Graduação em Psicologia. Natal, RN, Brasil Resumo: Embora historicamente a regulação proibitiva do incesto seja considerada um fenômeno cultural quase universal que não é influenciado por fatores psicobiológicos relativos à história evolutiva da espécie humana, evidências recentes têm questionado essa visão tradicional e defendido que a evitação e a proibição do incesto são influenciadas biológica e cognitivamente com a cultura. Este artigo objetiva desenvolver uma discussão teórica acerca da inibição e proibição do incesto, enfatizando os mecanismos evolutivos subjacentes a esses fenômenos. Argumenta-se a existência de mecanismos endógenos que evoluíram porque inibem a atividade sexual entre parentes próximos e que formam a base para regular socialmente a proibição do incesto (mecanismo exógeno). Destaca-se o efeito Westermarck, no qual a proximidade de pessoas que vivem juntas desde a infância provoca uma aversão ao intercurso sexual entre elas. A ausência de propensão ao incesto e sua proibição institucional constituem uma complexa integração entre fatores psicobiológicos e culturais. Palavras-chave: incesto, evitação, proibição, evolução. Introdução por ≥50% dos casamentos consanguíneos nessas popula- ções (Zlotogora, Hujerat, Barges, Shalev, & Chakravarti, O incesto é definido como a prática de relação 2007). Os casamentos consanguíneos de segundo e ter- sexual entre pessoas com graus próximos de parentesco, o ceiro graus oferecem vantagens, como fortalecimento dos qual pode ser de curto ou longo prazo, com ou sem geração laços e relações familiares, garantia de saber da história de de filhos (Lumsden & Wilson, 1980; Read, 2014; Tidefors, vida do cônjuge antes do casamento, facilidade de acertar Arvidsson, Ingevaldson, & Larsson, 2010). -
Chapter 51 Animal Behavior
Chapter 51 Animal Behavior Lecture Outline Overview: Shall We Dance? • Red-crowned cranes (Grus japonensis) gather in groups to dance, prance, stretch, bow, and leap. They grab bits of plants, sticks, and feathers with their bills and toss them into the air. • How does a crane decide that it is time to dance? In fact, why does it dance at all? • Animal behavior is based on physiological systems and processes. • An individual behavior is an action carried out by the muscular or hormonal system under the control of the nervous system in response to a stimulus. • Behavior contributes to homeostasis; an animal must acquire nutrients for digestion and find a partner for sexual reproduction. • All of animal physiology contributes to behavior, while animal behavior influences all of physiology. • Being essential for survival and reproduction, animal behavior is subject to substantial selective pressure during evolution. • Behavioral selection also acts on anatomy because body form and appearance contribute directly to the recognition and communication that underlie many behaviors. Concept 51.1: A discrete sensory input is the stimulus for a wide range of animal behaviors. • An animal’s behavior is the sum of its responses to external and internal stimuli. Classical ethology presaged an evolutionary approach to behavioral biology. • In the mid-20th century, pioneering behavioral biologists developed the discipline of ethology, the scientific study of how animals behave in their natural environments. • Niko Tinbergen, of the Netherlands, suggested four questions that must be answered to fully understand any behavior. 1. What stimulus elicits the behavior, and what physiological mechanisms mediate the response? 2. -