Birth seasonality in the early Spanish-Mexican colonists of California (1769-1898).

The pattern of birth seasonality in California's early Spanish-Mexican colonists between 1769 and 1898 was reconstructed using genealogical data for progeny of 657 marriages. The monthly distribution of the 3,824 births in this sample shows a strong seasonal pattern, with spring and fall peaks (corresponding to peaks in conceptions during July and February) and a low point in October. This seasonal reproductive pattern is the result of a complicated set of interactions among environmental, physiological, and cultural variables. California's strongly developed winter rainfall pattern and the 19th-century agricultural cycle clearly influenced the seasonal pattern of marriages and births in this agrarian society. Several historical processes interacted with these environmental and economic factors to transform the seasonal birth pattern of the early colonists. Through time the birth pattern becomes less variable and the birth maximum shifts from spring to early winter. This appears to be, at least in part, a result of changes in labor patterns and an increase in average parity. These data suggest a multifactorial explanation for birth seasonality, in which the timing of conceptions and births is influenced by both environmental and socioeconomic factors.

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

Marriage patterns of California's 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.

Genetic study of the population of Tenerife (Canary Islands, Spain): protein markers and review of classical polymorphisms.

Data on six protein polymorphisms (19 alleles) from the human population of Tenerife are presented and discussed along with other classical markers in relation to the origin of the Canarians. Genetic influences from three population groups were considered: the Iberians, and the Berbers and non-Berbers (Arabs) from north Africa. The systems examined show the Tenerife population lies within the limits of variation described for various Iberian groups, with a slight tendency towards the characteristics of north African populations. When blood groups, red cell enzymes and serum protein data were considered, the similarity of the Canary population to Iberians seems strengthened (70% estimated contribution of Iberian peninsula genes to the present-day Canarian pool), while some relation with north African groups is shown. Genetic distances between Canarians and Arabs and Canarians and Berbers are lower than those between the two north African groups, indicating a relative and comparable contribution of each to the present-day gene pool of the Canarian population. The Arab contribution could be attributable to the slaves who were introduced to these islands after the conquest in the 15th century, while the Berber contribution could be the remnants of the extinct aboriginal peoples of the islands (Guanches) or a more recent immigration due to slavery. Genetic data do not allow us to distinguish between these two possibilities.