The genetics of human sex ratio evolution

This study examined the hypothesis that natural selection exerts control of the human sex ratio via allelic variation in an autosomal gene that is phenotypically expressed in the male reproductive system. The hypothesis was supported by results from an analysis of a large genealogical dataset, in which inheritance of sex ratio variation by male but not female offspring was found. A series of simulations with a population genetic model showed that equality of the sex ratio may be maintained in a dynamic equilibrium by frequency dependent selection acting on such a gene. These simulations also suggest that long-term oscillations and autocorrelation between years in annual human sex ratio data may be explained by the hypothesis. A further set of simulations showed that an episode of increased male mortality - in a population with a sex ratio determined by the proposed gene - may result in a sudden increase in male births, provided the mortality is limited to a narrow cohort of males and that families with a greater tendency to have male offspring tend to be larger than those with a tendency to produce equal male and female offspring. To explore whether this could provide an explanation for significant increases in male births observed during periods of war, military service records and genealogical data were examined to determine the age structure of recruits to the British Army in the First World War and the typical age of fatherhood at the time. It was found that the cohort of men lost to the war were younger than men who typically became fathers. It was also found that families with offspring of a single sex tend to be larger than those with both sexes. As such, this work supports the hypothesis that the loss of young men in war results in a relative increase in male births, due to increased fatherhood by men from families with more male offspring (i.e. men with more brothers than sisters), because these men are most likely to have inherited a greater tendency to produce male offspring.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Long-Term Trends in Marriage Timing and the Impact of Migration, the Netherlands (1650-1899)

The features of historical marriage patterns have been linked to debates in social and economic history about economic growth and female agency. However, there is a lack of empirical evidence on the demographics of marriage prior to the nineteenth century. Here, we study trends in sex-specific ages at first marriage, regional variation and the impact of migration on marital timing in the Netherlands in the period 1650-1900. We make use of two new large historical datasets, namely an aggregation of Dutch genealogies and the transcribed marriage banns of Amsterdam. This allows us to understand the features and developments of marriage ages from a long-term perspective in what is known as one of the core-areas of the so-called European Marriage Pattern. Our results show high marriage ages for both sexes from the beginning of our study period, increasing until the mid-19th century. A closer look at regional variation reveals clear differences between the provinces and between urban and rural settings with those in the western part of the country and in urban centers marrying earlier. Migrating individuals married on average later than non-migrating individuals both compared to men and women in the receiving community, as to the ‘stayers’ in the location of origin. As later marriage implies a reduction of the window of fertility, especially for women, our results suggest that migration and increasing regional mobility might have been an important driver of the demographic shift toward higher marriage ages and lower fertility in Europe between the 17th and 19th centuries

Plasma Desmosine and Abdominal Aortic Aneurysm Disease

Background It is recognized that factors beyond aortic size are important in predicting outcome in abdominal aortic aneurysm (AAA) disease. AAA is characterized by the breakdown of elastin within the aortic tunica media, leading to aortic dilatation and rupture. The aim of this study was to investigate the association of plasma desmosine (pDES), an elastin-specific degradation product, with disease severity and clinical outcome in patients with AAA. Methods and Results We measured pDES and serum biomarker concentrations in 507 patients with AAAs (94% men; mean age, 72.4±6.1 years; mean AAA diameter, 48±8 mm) and 162 control subjects (100% men; mean age, 71.5±4.4 years) from 2 observational cohort studies. In the longitudinal cohort study (n=239), we explored the incremental prognostic value of pDES on AAA events. pDES was higher in patients with AAA compared with control subjects (mean±SD: 0.46±0.22 versus 0.33±0.16 ng/mL; P<0.001) and had the strongest correlation with AAA diameter (r=0.39; P<0.0001) of any serum biomarker. After adjustment for baseline AAA diameter, pDES was associated with an AAA event (hazard ratio, 2.03 per SD increase [95% CI, 1.02-4.02]; P=0.044). In addition to AAA diameter, pDES provided incremental improvement in risk stratification (continuous net reclassification improvement, 34.4% [95% CI, -10.8% to 57.5%; P=0.09]; integrated discrimination improvement, 0.04 [95% CI, 0.00-0.15; P=0.050]). Conclusions pDES concentrations predict disease severity and clinical outcomes in patients with AAA. Clinical Trial Registration http://www.isrctn.com. Unique identifier: ISRCTN76413758

¿QUIÉN DECIDE TENER VARON O HEMBRA? LA CIENCIA RESPONDE

Antes de iniciar esta corta noticia cient&iacute;fica, es preciso mencionar, que la misma no tiene la intenci&oacute;n de expresar un sesgo de g&eacute;nero, ni de herir susceptibilidades a nadie. Es s&oacute;lo describir hechos cient&iacute;ficos que puedenayudar a comprender nuestra realidad, interna y externa. En esta oportunidad queremos mostrar un estudio realizado por la Universidad de Newcastle que involucr&oacute; a miles de familias para ayudar a los futuros padres a determinar si es probable que tengan hijos o hijas. El trabajofue realizado por Corry Gellatly, un cient&iacute;fico investigador de esa universidad, demostr&oacute; que los hombres heredan la tendencia de tenerm&aacute;s hijos o m&aacute;s hijas de sus padres. Esto significa que un hombre con muchos hermanos tiene m&aacute;s probabilidades de tener hijos,mientras que un hombre con muchas hermanas tiene m&aacute;s probabilidades de tener hijas. Mientras que en las mujeres, simplemente no se puede predecir, seg&uacute;n el autor

The global male-bias in sex ratio at birth is sustained by the sex ratio genotypes of replacement offspring

Throughout the world, there is a male-bias in the sex ratio at birth (SRB). It is not known whether this phenomenon has a genetic basis, though there is tentative evidence from genealogical and genomic studies that it may have. It has been proposed that the higher rate of male childhood mortality in humans is linked to the male-bias in SRB through parental investment, but this may only apply to facultative not genetic sex ratio adjustment. In previous population genetic models, elevated mortality in one sex (prior to breeding) has been shown not to affect the SRB, but these models did not consider the role of replacement births (i.e. births that only occur because a sibling died prematurely). In a set of population genetic modelling simulations, in which sex ratio is controlled by an autosomal gene expressed in the male line, this study shows that when there is replacement of dead offspring, this leads to a sustained bias in the SRB in the direction of the sex suffering the highest mortality. In the example of higher male mortality, this occurs, because replacement offspring are disproportionately drawn from fathers who were genetically predisposed to have initially had sons (because sons were more likely to die prematurely), and more likely to pass on male-biasing alleles to replacement offspring. To test the empirical basis for replacement births, an analysis of birth data from the Demographic and Health Survey program was conducted, which shows that parents do indeed tend to replace children who die prematurely

NL, BE and DE first marriages and lifespans 1600-1899 (GO 924 set)

A data set of first marriages (including marriage location and ages of spouses at marriage) and lifespans of spouses (including year and location of births and deaths, where known), for marriages conducted between 1600 and 1899 in the Netherlands, Belgium and Germany. Also included is a binary indicator for whether the marriage, birth or death locations were urban or rural between 1600 and 1800, according to the coding system used by Bosker et al. 2013 [Rev. Econ. Stat., <st rong>95(4), 1418-1437 doi:10.1162/REST_a_00284]. The data set is derived from a genealogical database, which was constructed from family tree (GEDCOM) files contributed by users of www.genealogieonline.nl. The genealogical data from contributed files was error-checked before being combined into a single database using the TreeChecker application. From the initial pool of >1600 f iles contributed by the users of www.genealogieonline.nl, 924 files were included in the database after an assessment of the percentage of errors in each file, hence the database is known as the GO 924 set.Duplicate marriages were identified by the year of marriage and the first 7 letters of each spouse surname, whereupon a random duplicate was selected for inclusion in the data set. Note that names of individuals and exact dates of marria ges, births and deaths are excluded from this data set to prevent identification of individuals, as the genealogical data was provided to our research group on the basis that it would only be published in an aggregated or anonymised format. Access to the un-anonymised data may be granted subject to confidentiality agreements, please contact the authors for further information. Marriages were only included where the place of marriage had been checked and geocoded with latitude and longitude coordinates, where (as far as we could ascertain) it was the first marriage of the spouse, age at marriage was &gt; 13 for both spouses, all lifespans were &lt; 111 and no estimated dates were used to calculate spouse lifespan.The dataset is in a long format, in which there is a separate record for each spouse. It can be determined whether the spouse is the husba nd or wife (and conversely whether the other is the wife or husband) by the `spouse_sex` variable. A description of each variable is included in the text file accompanying the csv data file.</p

Long-Term Trends in Marriage Timing and the Impact of Migration, the Netherlands (1650-1899)

The features of historical marriage patterns have been linked to debates in social and economic history about economic growth and female agency. However, there is a lack of empirical evidence on the demographics of marriage prior to the nineteenth century. Here, we study trends in sex-specific ages at first marriage, regional variation and the impact of migration on marital timing in the Netherlands in the period 1650-1900. We make use of two new large historical datasets, namely an aggregation of Dutch genealogies and the transcribed marriage banns of Amsterdam. This allows us to understand the features and developments of marriage ages from a long-term perspective in what is known as one of the core-areas of the so-called European Marriage Pattern. Our results show high marriage ages for both sexes from the beginning of our study period, increasing until the mid-19th century. A closer look at regional variation reveals clear differences between the provinces and between urban and rural settings with those in the western part of the country and in urban centers marrying earlier. Migrating individuals married on average later than non-migrating individuals both compared to men and women in the receiving community, as to the ‘stayers’ in the location of origin. As later marriage implies a reduction of the window of fertility, especially for women, our results suggest that migration and increasing regional mobility might have been an important driver of the demographic shift toward higher marriage ages and lower fertility in Europe between the 17th and 19th centuries

Life histories of persons marrying, between 1600 and 1999, in the Netherlands [GO924]

A data set based on marriages conducted between 1600 and 1999 in the Netherlands. Includes information on lifespans and marriage ages of spouses (focal spouse and other), also location data for births, marriages and deaths. Includes information on lifespans and death locations of parents of the spouses. Includes information on whether the marriage, birth and death locations were urban or rural between 1600 and 1800, based on whether a place contained 5000 or more inhabitants (using a database developed by Bosker et al. 2013 [Rev. Econ. Stat., 95(4), 1418-1437 doi:10.1162/REST_a_00284]). The data set is derived from a genealogical database, which was constructed from family tree (GEDCOM) files contributed by users of www.genealogieonline.nl, via a program in which genealogists who were registered with the website were invited to contribute their family trees for scientific research purposes. The genealogical data from contributed files was error-checked before being combined into a single database using the TreeChecker application (http://www.treechecker.net). From the initial pool of >1600 contributed files, 924 files were included in the database after an assessment of the percentage of errors in each file, hence the database is known as the GO 924 set. Duplicate marriages were identified by the year of marriage and the first 7 letters of each spouse surname, whereupon a random duplicate was selected for inclusion in the data set. Note that names of individuals and exact dates of marriages, births and deaths are excluded from this data set to prevent identification of individuals, as the genealogical data was provided to our research group on the basis that it would only be published in an aggregated or anonymised format. Access to the un-anonymised data may be granted subject to confidentiality agreements, please contact the authors for further information. Marriages were only included where the place of marriage was in the Netherlands and marriage age of the spouse was > 13. The dataset is in a long format, in which there is a separate record for each spouse. It can be determined whether the spouse is the husband or wife (and conversely whether the other is the wife or husband) by the `spouse_sex` variable. A description of each variable is included in the accompanying text file: GO924_married_in_NL__VARIABLES.txt

Life histories of persons marrying, between 1600 and 1999, and dying, in the Netherlands [GO924]

A data set based on marriages conducted between 1600 and 1999 in the Netherlands. Includes information on lifespans and marriage ages of spouses (focal spouse and other), also location data for births, marriages and deaths. Includes information on lifespans and death locations of parents of the spouses. Includes information on whether the marriage, birth and death locations were urban or rural between 1600 and 1800, based on whether a place contained 5000 or more inhabitants (using a database developed by Bosker et al. 2013 [Rev. Econ. Stat., 95(4), 1418-1437 doi:10.1162/REST_a_00284]). The data set is derived from a genealogical database, which was constructed from family tree (GEDCOM) files contributed by users of www.genealogieonline.nl, via a program in which genealogists who were registered with the website were invited to contribute their family trees for scientific research purposes. The genealogical data from contributed files was error-checked before being combined into a single database using the TreeChecker application (http://www.treechecker.net). From the initial pool of >1600 contributed files, 924 files were included in the database after an assessment of the percentage of errors in each file, hence the database is known as the GO 924 set. Duplicate marriages were identified by the year of marriage and the first 7 letters of each spouse surname, whereupon a random duplicate was selected for inclusion in the data set. Note that names of individuals and exact dates of marriages, births and deaths are excluded from this data set to prevent identification of individuals, as the genealogical data was provided to our research group on the basis that it would only be published in an aggregated or anonymised format. Access to the un-anonymised data may be granted subject to confidentiality agreements, please contact the authors for further information. Marriages were only included where the place of marriage was in the Netherlands, marriage age of the spouse was > 13 and the spouse died in the Netherlands. The dataset is in a long format, in which there is a separate record for each spouse. It can be determined whether the spouse is the husband or wife (and conversely whether the other is the wife or husband) by the `spouse_sex` variable. A description of each variable is included in the accompanying text file: GO924_married_and_dying_in_NL__VARIABLES.txt