Clara García-Moro

Season of birth affects short‐ and long‐term survival

Recent research findings have highlighted the importance of early life conditions as risk factors for adult diseases and therefore determinants of subsequent survival. Given that individuals born during different seasons in seasonal environments experience different early-developmental conditions, an analysis of the effects of the season of birth on survival is considered an effective approach in clarifying the influence of early life conditions on survival in later life. In the present study, we analyzed the long-term effects of early developmental conditions in a historical population in which both nutritional levels and the burden of infectious diseases showed a seasonal variation. Using a semi-computerized linkage process, we were able to match birth and death data for 4,646 individuals born between 1634 and 1870 in the village of Es Mercadal (Minorca Island, Spain). To determine ecological differences associated with the season of birth, we first evaluated the association between season of birth and early life survival. This analysis helped us to determine seasonal variations in early life conditions such as infectious burden and nutritional levels. The season of birth had a significant effect on long-term survival in the birth cohort 1800-1870: summer births had a lower risk of death after age 15. We explain these results in terms of lower susceptibility to degenerative diseases in adult years due to superior in utero nutrition for summer births. These findings support the fetal origin hypothesis which states that the early life environment plays a key role in shaping the subsequent phenotype and risk of adult disease.

Time Series Analysis of the Epidemiological Transition in Minorca, 1634-1997

ABSTRACT Autoregressive integrated moving average (ARIMA) models provide a powerful tool for detecting seasonal patterns in mortality statistics. The strength of ARIMA models lies in their ability to reveal complex structures of temporal interdependence in time series. Moreover, changes in model parameters provide an empirical basis for detecting secular trends and death seasonality patterns. This approach is illustrated by our analysis of changes in the mortality patterns of the population of the town of Es Mercadal on the island of Minorca between 1634 and 1997. These data reveal a transition from an early mortality pattern requiring a complex ARIMA model that accounts for a strong seasonal death pattern and periodic epidemic-related mortality crises to a much simpler 20th-century pattern that can be described by a simple single-parameter ARIMA model. These same data were also analyzed using standard seasonality tests. The results show that the reduction in the number of parameters required to fit the Es Mercadal mortality data coincides with the epidemiological transition in which the predominant causes of morbidly and mortality shift from infectious to degenerative causes.

Epidemiological transition in Easter Island (1914-1996).

This study describes the mortality patterns during the present century (1914–1996) and investigates the epidemiological transition in a single community, Easter Island (Rapanui), the geographically most isolated inhabited island. Mortality patterns were reconstructed from civil records and included deaths of all island residents. The mean annual number of deaths is 9.3. A steady decline in the mortality rate linked to rapid modernization is the most relevant general trait. Although a small mortality crisis was detected in 9 years of the period studied, there was no significant seasonality in the deaths, possibly due to little climatic variation. The most serious sanitary problem was leprosy, endemic on the island from the end of the 19th century. Sanitary improvements, on one hand, and the effective breakdown of isolation, on the other, brought about the eradication of leprosy and the beginning of an epidemiological transition. In the latter years of the study, there was an increasing prevalence of degenerative diseases, connected, in part, with changes in the age structure of the population caused by the decline of mortality. A correspondence analysis shows the relationships between causes of death and age, and makes clear the different incidence of disease by age. The infant mortality rates were lower than in the Chilean population. Am. J. Hum. Biol. 12:371–381, 2000.

Genetic Relationships Between Parishes in the Ebro Delta Region (Spain) as Estimated by Migration Matrix and Surnames

ABSTRACT To determine whether there are preferential relationships among individuals from the different parishes of the Ebro River delta region, we analyzed the population relationships, taking into account both the birthplaces of the spouses and their surname frequencies. We used data from the 9,085 marriages recorded in the Ebro delta area between 1939 and 1995. Using each spouses birthplace, we calculated the distances between the subject populations by means of the squared Euclidean distance. Also, from the surname frequencies in the marriages we obtained certain kinship measurements. In both analyses the results show a clear differentiation between the parish of Amposta and the rest of the parishes. This difference is mainly due to a greater number of marriages in which delta outsiders participated and can be related to the greater surname diversity and lesser endogamy observed in this population. On the other hand, if only endogamous marriages are taken into account, there is clearly a differentiation between the parishes from both banks of the river, with a strong homogeneity among the north-side parishes. We compared the distances obtained from the birthplaces, the kinship parameters obtained from the surnames, and two geographic distance matrixes by means of a Mantel test, and the results show a strong and significant correlation between them when all marriages are considered. If, on the other hand, only endogamous marriages are taken into account, the barrier effect of the river on the interparish relationships can be appreciated.

Marriage patterns of California's early Spanish-Mexican colonists (1742-1876)

Marriage patterns of Californias eighteenth and nineteenth century Spanish-Mexican families are analysed using data from genealogies and mission records. A shortage of women among the military based colonists led to an unusual marriage pattern with a large age differential between husbands and wives. The average age at marriage was 18.4 years for women and 28.4 years for men. Spatial mobility was high for both sexes, particularly for men. More husbands than wives were born in Mexico. The Monterey presidial district of central California was the birthplace of a disproportionate number of husbands and the southern California districts were a source of wives. The transition between a founding population predominantly composed of Mexican immigrants and a population of native-born Californians occurred at the beginning of the nineteenth century.

Y-Chromosome-Specific STR Haplotype Data on the Rapanui Population (Easter Island)

ABSTRACT Located in the south Pacific Ocean, Rapanui is one of the most isolated inhabited islands in the world. Cultural and biological data suggest that the initial Rapanui population originated from central Polynesia, although the presence of foreign or exotic genes in the contemporary population, as a result of admixture with Europeans and/or South Americans during the last two centuries, also has to be considered. To estimate the genetic affinities of the Rapanui population with neighboring populations, we analyzed seven microsatellite polymorphisms of the Y chromosome that recently have been indicated as useful in the study of local population structure and recent demographic history. Phylogenetic analysis of Rapanui Y-chromosome haplotypes identified two clusters. The largest cluster contained 60% of all haplotypes and is characterized, in particular, by the presence of the DYS19*16, DYS390*20, and DYS393*14 alleles, a combination found frequently in Western Samoa. The second cluster is characterized by the presence of the DYS19*14, DYS390*24, and DYS393*13 alleles, and these have a relatively high frequency in European and European-derived populations but are either infrequent or absent in native Pacific populations. In addition to the two clusters, one male is of haplogroup Q*, which is indicative of native American ancestry. The genetic structure of the current male population of Rapanui is most likely a product of some genetic contribution from European and South American invaders who mated with the indigenous Polynesian women. However, analysis of Rapanuis relationships with other Pacific and Asian populations indicates that, as in Western Samoa and Samoa, the population has experienced extreme drift and founder events.

ESTACIONALIDAD DE NACIMIENTOS, MATRIMONIOS Y DEFUNCIONES EN LA REGIÓN MAGALLÁNICA. COMPARACIÓN CON LA ÉPOCA DE LA COLONIZACIÓN

ESTACIONALIDAD DE NACIMIENTOS, MATRIMONIOS Y DEFUNCIONES EN LA REGION MAGALLANICA. COMPARACION CON LA EPOCA DE LA COLONIZACIONMIGUEL HERNANDEZ*, CLARA GARCIA-MORO* & MIREIA ESPARZA*RESUMEN Se ha estudiado la estacionalidad de los nacimientos, matrimonios y defunciones en la region magallanica en el periodo 1997-2009. Los nacimientos son mas frecuentes entre los meses de abril a octubre, mientras que los matrimonios presentan un maximo en verano y las defunciones en invierno. Los resultados actuales muestran diferencias significativas con los de la epoca de la colonizacion que pueden explicarse por los cambios socioeconomicos.PALABRAS CLAVE: estacionalidad, Magallanes, tiempo presente, colonizacion, cambio socioeconomico.ABSTRACTSEASONALITY OF BIRTHS, MARRIAGES AND DEATHS IN THE MAGELLAN REGION. COMPARISON WITH THE TIME OF SETTLEMENT The seasonality of births, marriages and deaths in the Magellan region in the period 1997-2009 has been studied. Births are most common between the months of April to October, while marriages have a peak in summer and deaths are more frequent in winter. These results show significant differences with those obtained for the time of settlement which may be explained by socioeconomic changes.KEY WORDS: seasonality, Magellan, present time, settlement, socioeconomic change.

FERTILITY PATTERN AND FITNESS OF THE SPANISH-MEXICAN COLONISTS OF CALIFORNIA (1742-1876).

The analysis of fertility in colonizing populations is of great interest, since its individuals experience a major environmental change, and fertility rates can reflect the level of adaptation of the population to its new conditions. Using Northrops genealogical compilations, this paper examines the fertility pattern of Californias early Spanish-Mexican colonists between 1742 and 1876, their fitness levels and their trend across time throughout the colonizing period. A total of 197 women from 599 compiled families who had completed their reproductive period and had at least one child were analysed. The correlations among variables were also analysed in order to infer the relationship between longevity and fertility, and the influence of fertility determinants. The results show a natural fertility pattern, with a very young age at marriage and birth of first child (17.2 and 19.1 years respectively), and also a young age at last childbirth (38.8 years). The populations fitness showed greater values than for contemporary European populations, with 8 of 9.2 children surviving to adulthood, in comparison with 55% of newborns in Finland for the same period, suggesting a good adaptation of the population to their new environmental conditions. No relationship between fertility and lifespan was observed, as has been reported by other authors and in opposition to classical theories. A temporal trend in the number of children, consisting of three different phases, was observed, in accordance with the stability of living conditions in the region.

HISTORIA REPRODUCTORA Y FECUNDIDAD DE LAS MUJERES CHILENAS DE TIERRA DEL FUEGO

RESUMENEl presente estudio analiza la informacion obtenida a traves de 182 encuestas de fecundidad amujeres en edad posreproductora de la Tierra del Fuego chilena. La muestra es representativa de lapoblacion femenina fueguina desde casi el inicio de la colonizacion. Se describen los distintos even-tos e intervalos que definen la historia reproductora de estas mujeres, ademas de sus valores defecundidad y de fecundidad marital. Su vida reproductiva, toda ella transcurrida en la isla, se carac-teriza por un largo intervalo fertil, un corto intervalo fecundo y una reducida fecundidad, y se cons-tata como la mayor eficiencia de uso de sus anos reproductores se traduce en un tamano de laprogenie mayor. Finalmente, se realizan dos aproximaciones distintas al estudio de los determinantesde la fecundidad de las mujeres de la poblacion: por un lado, el analisis mediante el modelo agregativode la fecundidad descrito por Bongaarts y Potter y, por otro, la aplicacion del path analysis . Lospatrones de nupcialidad, el ritmo de concepcion y las practicas de anticoncepcion son propuestoscomo los principales determinantes de la fecundidad en las mujeres chilenas de Tierra del Fuego.PALABRAS CLAVES: Fecundidad, determinantes proximos,

Migration and isolation effects on the Rapanui population (Easter island) through the analysis of STRs on the Y chromosome

Cultural and biological data suggests the Polynesian origin of the Rapanui population, although the presence of foreign genes in the native population, as a result of admixture with Europeans in the last two centuries has also to be considered. In order to estimate the genetic affinities of the present-day inhabitants of Easter Island and the nearby populations, we used seven polymorphisms of the Y chromosome. However we want to estimate the grade of admixture on the genetic structure that was brought from foreigners within the last two centuries upon the more geographically isolated populations in the world.The preliminary results showed the presence of 18 haplotypes analyzed on 30 male samples.The analysis of the allelic frequency showed a distribution typical of the Polynesian populations. Available data in literature, even with some differences probably due to either the founder effect or historical and ecological events that created sudden demographic variations on the island population. The phylogentic analysis of the haplotypes obtained through Network Median Joining showed two different cluster of haplotypes, of which one represents about 64% of the present haplotypes on Easter Island, which are characterized from the presence of the allele DYS19*16, very frequent in the Pacific populations. The other cluster is characterized from the presence of the allele DYS19*14, absent within the populations in the Pacific and with reasonable high frequency within the European populations and South American. Most probably the two clusters are the product of several colonizations that Easter Island had endured from the time of the Chilian and European Colonies. It was demonstrated in fact, that the arrival in 1914 of 50 German and English prisoners would have left a considerable genetic impact on the population of Rapanui, which during this period was of small size.