Ethnic Identity and Genome Wide Runs of Homozygosity.

It is long known that inbreeding increases the detrimental effects of recessive sequence variants in "Runs of Homozygosity" (ROHs). However, although the phenotypic association of ROH has been investigated for a variety of traits, the statistical power of the results often remains limited as a sufficiently high number of cases are available for only a restricted number of traits. In the present study, we aim to analyze the association of runs of homozygosity with the trait "in-group ethnic favoritism". This analysis assumes that if ethnic identity is important for an individual, that individual may tend to marry more frequently within their own group and therefore ROH are expected to increase. We hypothesize that an attitude preferring one's own ethnic group may be associated with a stronger tendency of inbreeding and, as a result, with more and longer ROHs. Accordingly, we investigated the association between the attitude to someone's own ethnicity and ROH, using the Wisconsin Longitudinal data (WLS, total N ~ 9000) as discovery data set and the Brisbane Twin data as replication data set (N ~ 8000). We find that both the number as well as the total length of homozygous segments are significantly positively associated with "in-group ethnic favoritism", independent of the method used for ROH calculation.

Factors affecting attitudes toward migrants-An evolutionary approach.

OBJECTIVE: To understand migration from an evolutionary perspective, this phenomenon has so far been mainly investigated in animal species. We therefore aim to investigate the potential evolutionary roots of attitudes toward migrants in humans. METHODS: We used data from the European Social Survey (n = 83 734), analyzing attitudes toward migrants by performing ordinal mixed models. RESULTS: We found that men have a more restrictive attitude toward migration than women, which increases with age and is stronger with a child in the household. Attitude toward migrants is also more skeptical if migrants have a different ethnicity and are from poorer countries. Increasing education and religiousness are associated with a more positive attitude toward migrants, particularly toward migrants of different ethnicity and from poorer countries. DISCUSSION: Although migration flows are a hallmark of the human species, previous findings suggest that (pre-)historic migration flows were at times accompanied by conflict and violence, while at the same time, they insured survival by allowing cultural exchange and the avoidance of inbreeding. Accordingly, we assume that contemporary attitudes toward migration are rooted in our evolutionary past. We discuss the respective behavioral patterns from an evolutionary perspective, arguing that both-a negative attitude as well as openness-make sense.

Fertility Outcomes, Heritability and Genomic Associations of In-Group Preference and In-Group Marriage.

Using data from the Midlife Development in the USA (MIDUS) sample (3070 men and 3182 women) and the Wisconsin Longitudinal Study (WLS; 2240 men and 2346 women), we aimed to investigate whether religious, ethnic and racial in-group preferences as well as religious homogamy are associated with reproductive outcome in terms of number of children. Using data from the MIDUS twin sample, we further estimated the inherited genetic component of in-group attitudes. Additionally, we analyzed the association of ∼50 polygenic scores (PGSs) recently published for the WLS study and in-group attitudes as an indicator of potential pleiotropic effects. We found in both samples that, with one exception, religious though not other in-group attitudes are associated with a higher reproductive outcome. Also, religious homogamy is associated with higher average number of children. The inherited component of all in-group attitudes ranges from ∼21% to 45% (MIDUS twin sample). PGSs associated with religious behavior are significantly positively associated with religious in-group attitudes as well as family attitudes. Further associations are found with PGS on life satisfaction (work) and, negatively, with PGS for any sort of addiction (smoking, alcohol and cannabis use), indicating pleiotropy. We conclude that the positive association between religious in-group attitudes as well as religious homogamy and reproductive outcome may indicate selective forces on religious in-group behavior. As all investigated in-group attitudes, however, have a substantial inherited component, we further speculate that potential previous reproductive benefits of racial and ethnic in-group preferences, if they ever existed, might have been substituted by religious in-group preferences.

Do birds of a feather flock together? Factors for religious heterogamy.

Social cohesion - particularly with regard to the integration of migrants - is primarily measured in terms of education, labour market participation, unemployment, income levels and poverty. When seen from a historical long-term perspective (considering the migrations of Homo sapiens in the past 300,000 years) admixture merged members of diverse groups and forged - in addition to social ties - 'strong biological ties' of kinship, proposing that religious heterogamy is a long-term layer of social cohesion. Accordingly, this study investigated, on the basis of more than 600,000 men and women aged 26-35 years from Austria 2001, Germany (West) 1987, Ireland 2011, Portugal 2011, Romania 2011 and Switzerland 2000, which demographic characteristics foster religious heterogamy, controlling for various confounding factors using linear mixed modelling. By far the most important factor explaining religious heterogamy was the share of adherents to an individual's religious group in their area of residence. It can be concluded that the rate of intermarriage declines with the increasing size of an individual's religious group in their area of residence. From a long-term perspective the lack of familial ties (and conjoint offspring) between religious groups could lead to a lack of social cohesion.

Mutual compensation of the effects of religious and ethnic homogamy on reproduction.

OBJECTIVES: Homogamy, mating based on similarity, has been demonstrated for a great variety of traits such as age, education, religion, and physical and psychological traits. Recently, pro-fertile effects of religious as well as educational homogamy have been reported. We investigate whether ethnic homogamy also has a pro-fertile effect and whether ethnic and religious homogamy interact in their putative effects on reproduction (in terms of average number of offspring). METHODS: We analyzed the association between ethnic as well as religious homogamy and woman's average number of offspring based on census data from ten countries provided by IPUMS international, encompassing a total of 1,485,433 married women aged 46-60 years (who have thus completed or almost completed reproduction) and their spouses. RESULTS: We find a clear pro-fertile but nonadditive effect of both ethnic and religious homogamy, which is most pronounced in the case of double homogamy. Our results further indicate that homogamy for one trait may compensate for heterogamy of the other, albeit countries differ regarding which trait compensates for the other. CONCLUSIONS: We suggest that the interaction between ethnic homogamy, religious homogamy, and reproduction provides an interesting example for gene-culture co-evolution.

MARRIAGE GAP IN CHRISTIANS AND MUSLIMS.

For modern Western societies with a regime of monogamy, it has recently been demonstrated that the socioeconomic status of men is positively associated with being or having been married. This study aims to compare marriage patterns (if a person has been married at least once) for cultures with a tradition of monogamy and polygyny. As no worldwide data on polygyny exist, religion was used as a proxy for monogamy (Christians) vs polygyny (Muslims). The analyses were based on 2000-2011 census data from 39 countries worldwide for 52,339,594 men and women, controlling for sex, sex ratio, age, education, migration within the last 5 years and employment. Overall, a higher proportion of Muslims were married compared with Christians, but the difference in the fraction of married men compared with married women at a certain age (the 'marriage gap') was much more pronounced in Muslims than in Christians, i.e. compared with Christians, a substantially higher proportion of Muslim women than men were married up to the age of approximately 31 years. As expected for a tradition of polygyny, the results indicate that the socioeconomic threshold for entering marriage is higher for Muslim than Christian men, and Muslim women in particular face a negative effect of socioeconomic status on the probability of ever being married. The large 'marriage gap' at a certain age in Muslim societies leads to high numbers of married women and unmarried young men, and may put such polygenic societies under pressure.

The association between religious homogamy and reproduction.

Individuals more strongly affiliated to religion have on average more children than less religious ones. Here, based on census data of 3 658 650 women aged 46-60 years from 32 countries provided by IPUMS International and data from the Wisconsin Longitudinal Study (n = 2400 women, aged 53-57 years), we show that religious homogamy is also associated with higher reproduction in terms of a higher number of children and a lower chance of remaining childless. We argue that, together with the relationship between general religious intensity and number of children, religious homogamy has reproductive consequences. These may impact future demographic developments and could have also played a role in the biological evolution of humans.

Allelic variation of the COMT gene in a despotic primate society: A haplotype is related to cortisol excretion in Macaca fuscata.

Sequence variations in genes of the monoamine neurotransmitter system and their common function in human and non-human primate species are an ongoing issue of investigation. However, the COMT gene, coding for the catechol-O-methyltransferase, has not yet attracted much scientific attention regarding its functional role in non-human primates. Considering that a polymorphism of the human COMT gene affects the enzyme activity and cortisol level in response to a social stressor, this study investigated the impact of COMT on endocrine stress and behavioural parameters in Japanese macaques (Macaca fuscata). The species exemplifies a despotic hierarchy in which males' social rank positions require an adaptation of behaviour strategies. During the mating period steroid secretion and the frequency of aggressive encounters between males increase. We addressed i) whether this species exhibits potential functional COMT variants, ii) whether these variants are associated with faecal cortisol excretion of males, iii) how they are distributed among different social rank positions and iv) whether they are associated with behavioural strategies during times of mate competition. By genotyping 26 males we identified three COMT haplotypes (HT), including a putative splice mutant (HT3). This variant was associated with increased cortisol excretion. Given the observed inverse correlation between cortisol and physical aggression, we assume that different COMT haplotypes may predispose individuals to pursue more or less aggressive strategies. How these gene-stress effects might favour a specific social role is discussed. Our study of non-invasive genotyping in combination with behavioural and endocrine parameters represents an important step towards the understanding of gene-stress effects in a hierarchically organised primate society.

Signatures of positive selection in the cis-regulatory sequences of the human oxytocin receptor (OXTR) and arginine vasopressin receptor 1a (AVPR1A) genes.

BACKGROUND: The evolutionary highly conserved neurohypophyseal hormones oxytocin and arginine vasopressin play key roles in regulating social cognition and behaviours. The effects of these two peptides are meditated by their specific receptors, which are encoded by the oxytocin receptor (OXTR) and arginine vasopressin receptor 1a genes (AVPR1A), respectively. In several species, polymorphisms in these genes have been linked to various behavioural traits. Little, however, is known about whether positive selection acts on sequence variants in genes influencing variation in human behaviours. RESULTS: We identified, in both neuroreceptor genes, signatures of balancing selection in the cis-regulative acting sequences such as transcription factor binding and enhancer sequences, as well as in a transcriptional repressor sequence motif. Additionally, in the intron 3 of the OXTR gene, the SNP rs59190448 appears to be under positive directional selection. For rs59190448, only one phenotypical association is known so far, but it is in high LD' (>0.8) with loci of known association; i.e., variants associated with key pro-social behaviours and mental disorders in humans. CONCLUSIONS: Only for one SNP on the OXTR gene (rs59190448) was a sign of positive directional selection detected with all three methods of selection detection. For rs59190448, however, only one phenotypical association is known, but rs59190448 is in high LD' (>0.8), with variants associated with important pro-social behaviours and mental disorders in humans. We also detected various signatures of balancing selection on both neuroreceptor genes.

Paternal age predicts offspring chances of marriage and reproduction.

OBJECTIVES: Mutation-selection balance theory proposes that a balance of forces between constantly arising mildly harmful mutations and selection causes variation in genetic configuration and phenotypic condition. As mutations are predominantly deleterious, the entry of variation due to mutations is kept at low frequencies by selection. It has recently been demonstrated that nearly all de novo mutation are caused by paternal age. METHODS: We examined on basis of the Wisconsin Longitudinal Study (n = 6,182) whether a subject's probability of having ever married as well as having ever reproduced is associated with that subject's father's age at subject's birth. RESULTS: We find that advanced paternal but not maternal age at subject's birth predicts a lower chance of ever being married and a higher chance of childlessness, even controlling for various confounders. CONCLUSIONS: As marriage is a prerequisite of reproduction in this sample, we discuss that mate choice may provide a mechanism to prevent too high mutation load in the progeny.

Detecting month and year of birth effects on reproduction and marriage patterns in two long-term data sets.

This study examines the effects of birth month on reproduction and mating behavior using historical and contemporary census data from 1820 to 1970. The research examines the effect of birth month on the number of children for women and their male spouses, finding a monthly cycle for both men and women. In addition, the study examines whether birth month influences whether a person has ever been married. In support of previous research, we find clear birth month effects on the number of children for both women and their spouses, while the time series of ever being married shows a 60-month and a 10-year cycle, the latter possibly related to the solar cycle. Although the effects are small, both results, based on a large and representative dataset, indicate the importance of early life factors on mating and reproduction.

Attitudes towards Technology: Insights on Rarely Discussed Influences on Older Adults' Willingness to Adopt Active Assisted Living (AAL).

BACKGROUND: European research policy promotes active assisted living (AAL) to alleviate costs and reach new markets. The main argument for massive investments in AAL is its potential to raise older adults' Quality of Life and enhance their freedom, autonomy, mobility, social integration, and communication. However, AAL is less widely spread in older adults' households than expected. RESEARCH AIM: We investigate how the variable "technology acceptance" is connected to socio-economic-, social, health, "personal attitude towards ageing", and "Quality of life" variables. METHOD: We conducted a study in Vienna between 2018 and 2020, questioning 245 older adults (M = 74, SD = 6.654) living in private homes. We calculated multivariate models regressing technology acceptance on the various exploratory and confounding variables. RESULTS: Experiencing an event that made the person perceive their age differently changed the attitude towards using an assistive technological system. Participants perceived technology that is directly associated with another human being (e.g., the use of technology to communicate with a physician) more positively. CONCLUSION: Older adults' attitudes towards technology may change throughout their lives. Using major events in life as potential entry points for technology requires awareness to avoid reducing the lives of older adults to these events. Secondly, a certain human preference for "human technology" may facilitate abuse if technology is given a white coat, two eyes, a nose, and a mouth that may falsely be associated with a natural person. This aspect raises the ethical issue of accurate information as a significant precondition for informed consent.

Facial attractiveness is only weakly linked to genome-wide heterozygosity.

Introduction: It has been frequently suggested that overall genomic heterozygosity and, particularly, heterozygosity of loci on the so-called major histocompatibility complex (MHC), which is responsible for the recognition of foreign substances/ pathogens and the recognition of self and non-self, is associated with better health and better resistance to infections and parasites. It has further been speculated that such a potentially beneficial heterozygosity can be detected through body odor and facial attractiveness. Methods: On the basis of genome wide SNP data (713,014 SNPs) of participants from the Wisconsin Longitudinal Study, we therefore investigated whether homozygosity either on the MHC (measured as inbreeding coefficient) or genome-wide (measured as runs of homozygosity and inbreeding coefficient) is associated with rated facial attractiveness. Results: Although we found that the genome-wide average length of homozygous segments and the genome-wide inbreeding coefficient are significantly negatively associated with some measures of facial attractiveness, if corrected for multiple testing, any significant association was no longer formally significant after correction. In addition, the variance in facial attractiveness explained by the genome wide homozygosity is very low (<0.15%). We did not find any significant association between the inbreeding coefficient on the MHC and facial attractiveness. Discussion: We only find a weak association of genome- wide heterozygosity and facial attractiveness.

Increasing pressure on US men for income in order to find a spouse.

In contemporary societies, social status - especially income - is one of the most important determinants of ever marrying among men. Using U.S. census data, we estimated the importance of income for ever marrying among men and women, analyzing birth cohorts from 1890 to 1973. We examined individuals between the ages of 45 and 55, a total of 3.5 million men and 3.6 million women. We find that for men, the importance of income in predicting ever being married increased steadily over time. Income predicted only 2.5% of the variance in ever marrying for those born in 1890-1910, but about 20% for the 1973 cohort. For women, the opposite is true: the higher a woman's income among those born between 1890 and 1910, the lower her odds of ever being married, explaining 6% of the variance, whereas today a woman's income no longer plays a role in ever being married. Thus, our results provide evidence that income may represent a very recent selection pressure on men in the US, a pressure that has become increasingly stronger over time in the 20th and early 21st centuries.

Marriage in the Melting Pot: An Evolutionary Approach to European Ancestry, Homogamy, and Fertility in the United States.

To understand marriage patterns, homogamy, and fertility of women of European ancestry in the United States from an evolutionary perspective, we investigated if a prevalence of ancestral homogamy exists, the factors influencing a female preference for an ancestral homogamous vs. heterogamous marriage, and if ancestral homogamous vs. heterogamous marriages have an impact on fertility. Furthermore, we aim to determine the heritability of homogamous vs. heterogamous marriage behavior. We used the census data of 369,121 women in the United States married only once and aged between 46 and 60 years, provided by IPUMS USA (https://usa.ipums.org/usa/). We used linear mixed models to determine the association between the probability of a homogamous vs. heterogamous marriage and the individual fertility of women. We aimed to estimate the heritability (genetics and parental environment) of marriage behavior using a linear mixed model. We found that ancestral heterogamous marriages are more frequent compared to homogamous marriages, but only if all ancestry groups are included. If ancestry is aggregated, homogamous marriages are more frequent compared to heterogamous marriages. Most of the variance (up to 27%) in inter-ancestry marriage and fertility (up to 12%) is explained by ancestry per se, followed by the ratio of individuals of a certain ancestral background in a county (∼6%), indicating a frequency depending selection into marriage: the more individuals of a certain ancestry live in a county, the lower is the tendency to marry someone of a different ancestral background. Furthermore, we found that about 12% (depending to some extent on the clustering) of the marriage behavior is heritable. Being in a homogamous marriage and the income of the spouse are both significantly positively associated with the number of children women have and the probability that women have at least one child, albeit explaining only a very low proportion of the overall variance. The most important factor (in terms of variance explained) for being in an ancestral homogamous vs. heterogamous marriage, for the number of children, and for childlessness is the ancestry of the women. Most children are born to women of Irish, French, and Norwegian ancestry (Irish X̄: 3.24, French X̄: 3.21, and Norwegian X̄: 3.18), the lowest number of children is to women of Latvian, Rumanian, and Russian ancestry (Latvian X̄: 2.26, Rumanian X̄: 2.19, and Russian X̄: 2.35). Albeit, we are not able to distinguish the genetic and social heritability on the basis of our data, only a small heritability for in-group vs. out-group marriage behavior is indicated (∼12% of variance explained).

Stuck in the Present: A Human Lack of Ability to Visualise (Different) Needs in the Future May Hamper Timely Implementation of AAL and Supportive Technology.

Cities face an evident demographic change, making assistive technologies (AAL) an interesting choice to support older adults to autonomously age in place. Yet, supportive technologies are not as widely spread as one would expect. Hence, we investigate the surroundings of older adults living in Vienna and analyse their "socio relational setup", considering their social integration and psychophysical state compared to others (health, fitness, activeness, contentedness). Method: Our data included 245 older adults (age: M = 74, SD = 6654) living in their own homes (2018-2020 with different grades of needing support). We calculated univariate and multivariate models regressing the socio-relational setup on the change of routines, technology attitude, mobility aid use, internet use, subjective age, openness to move to an institutional care facility in the future, and other confounding variables. Results: We found a strong correlation between all categories (health, fitness, activeness, contentedness) of older adults comparing themselves to their peers. Among others, they are significantly related to institutional care openness, which implies that participants who felt fitter and more active than their peers were less clear in visualising their future: unpleasant circumstances of ageing are suppressed if the current life circumstances are perceived as good. This is an example of cognitive dissonance.

Unveiling the Genetic History of the Maniq, a Primary Hunter-Gatherer Society.

The Maniq of southern Thailand is one of the last remaining practicing hunter-gatherer communities in the world. However, our knowledge on their genetic origins and demographic history is still largely limited. We present here the genotype data covering ∼2.3 million single nucleotide polymorphisms of 11 unrelated Maniq individuals. Our analyses reveal the Maniq to be closely related to the Semang populations of Malaysia (Malay Negritos), who altogether carry an Andamanese-related ancestry linked to the ancient Hòabìnhian hunter-gatherers of Mainland Southeast Asia (MSEA). Moreover, the Maniq possess ∼35% East Asian-related ancestry, likely brought about by recent admixture with surrounding agriculturist communities in the region. In addition, the Maniq exhibit one of the highest levels of genetic differentiation found among living human populations, indicative of their small population size and historical practice of endogamy. Similar to other hunter-gatherer populations of MSEA, we also find the Maniq to possess low levels of Neanderthal ancestry and undetectable levels of Denisovan ancestry. Altogether, we reveal the Maniq to be a Semang group that experienced intense genetic drift and exhibits signs of ancient Hòabìnhian ancestry.

Perinatal winter conditions affect later reproductive performance in Romanian women: intra and intergenerational effects.

OBJECTIVES: To compare epidemiological studies on Austrian and New Zealand women that report below average reproductive performance after birth in summer, with a similar study in Romanian women. METHODS: We examined the association between birth month and offspring count analyzing census data from Romania obtained from IPUMS International (Population and Housing Census of Romania, year 2002), totaling 411,270 women aged older than 45 years. We investigated whether socio-economic status affected this association, and whether intergenerational effects exist for mother's birth month in relation to their daughter's offspring number. RESULTS: The time series of mean offspring count per birth month has a highly significant period of 12 months. Contrary to our expectations, average offspring count is highest in women born in June and lowest in those born in December, with a strong coincidence between negative peak values of residuals of mean offspring count per birth month and corresponding monthly means of ambient temperature in Romania. The association between winter birth and lower offspring number is significant in poorly educated women only. For mothers born in winter there is also an association with a lower daughters' offspring count. CONCLUSIONS: Conflicting results exist between Romania and Austria/New Zealand, and may be most easily explained by women's different exposure to winter conditions in these countries.

Socioeconomic status, marital status and childlessness in men and women: an analysis of census data from six countries.

This study compares the effects of two distinct forms of human capital - income and education - on marital status and childlessness separately by sex in six different countries. Nearly 10 million individual records on individuals aged 16 to 50 were used from censuses from Brazil, Mexico, Panama, South Africa, USA and Venezuela dating from 2000 or later, to analyse the relationship between education, income and marital status and childlessness in men and women. Regarding income, the findings for both outcome variables are strongly consistent across all six countries. Highest-income males and lower-income females have the highest proportion of ever-married and the lowest proportion of childlessness (using a proxy for childlessness: own children in the household or not). There is no corresponding consistency of findings as regards education either between the sexes or among the countries. To conclude, a lower percentage of low-income men are selected by females, because for women male status and resources provided by men are important criteria in mate selection. Therefore a higher proportion of low-income men remain unmarried and childless. Thus selection seems to play a role in modern societies.

Let's Walk It: Mobility and the Perceived Quality of Life in Older Adults.

European policy and the research and development landscape put forward a number of arguments in favor of implementing "Active Assisted Living" (AAL) for older adults: it will improve older adults' quality of life, allow them to age in place, and keep costs for an ageing society down by exploiting new technology markets. The idea is that older adults who are supported by AAL and make use of assistive technologies will enjoy more freedom, autonomy, and mobility and also improved social integration and better communication. Yet, despite a history of more than 10 years of European research and development, the use of AAL applications is not as widespread as expected. To examine older adults' attitudes to assistive technologies, we conducted a study in Vienna (Austria) between 2018 and 2020 questioning 245 older adults aged 61-93 years (M = 74.27 SD = 6.654) who lived at their private homes and had different support needs (ranging from "no support" to "everyday visit of social and/or care organizations"). The three goals of the study encompassed: (1) examination of their quality of life, (2) their attitudes and use of assistive technologies, and (3) the way they perceive their own and others' life-course and getting older. AAL as a concept links "ageing in place" and "quality of life". However, "mobility" is also of major importance here. In this paper, we aim to investigate the relation between the independent variables "Quality of life" and "Mobility" and their possible associations with the following dependent variables: cohabitation, social integration, self-rated health, sportive activities, locomotion, home well-being and safety, physical limitations, falls, and self-perception of their own ageing (compared to others). We calculated multivariate models regressing on these explaining and confounding variables. We found a positive correlation between mobility and quality of life. In detail, our results show a significant positive association between QOL and mobility regarding self-rated health and self-perception. Experiencing vertigo, walking difficulties, and balance problems significantly and negatively influence self-rated health and self-perception compared to others. Our findings can also be read as a clear message that there is a need to improve both health and the culture of ageing and to facilitate positive attitudes toward ageing as an efficient way to enhance the Quality of life of older adults.