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Chum salmon populations in the Russian Far East have a complex multi-level genetic structure. A total of 53 samples (2446 fish) were grouped into five major regional clusters: the southern Kurils, eastern Sakhalin, southwestern Sakhalin, the Amur River, and a northern cluster. The northern cluster consists of chum salmon populations from a vast geographical region, including Chukotka, Kamchatka, and the continental coast of the Sea of Okhotsk. However, the degree of its genetic differentiation is low, 1.9%. In contrast, the southern population cluster exhibits much higher variation; for example, differentiation between chum salmon groups within Sakhalin Island reaches 4.6%, and the differentiation between Iturup Island and Sakhalin Island chum salmon is 7.7%. This suggests that southern populations of Asian chum salmon have a more ancient evolutionary history than northern populations. In contrast to the available data, our study indicates a great deviation of southwestern Sakhalin populations from other Sakhalin chum salmon. The Russian Far East chum salmon are genetically diverse and show statistically significant differentiation even within small geographic localities. This can be used to assign samples of unknown origins to definite local populations. [ABSTRACT FROM AUTHOR]

A retrospective sample survey of birth certificates from a Moscow maternity hospital over a 40-year period has revealed secular growth changes (involving mothers' stature, age at menarche, and four anthropometric traits in newborns) in two consecutive generations. Cohorts of mothers born in the period 1930-1949 showed high rates of acceleration. Age at menarche decreased in these cohorts at a rate of 12.5 months per 10 years, and a parallel gain in stature averaged 1.8 cm per 10 years; both rates were significantly higher than those for Western Europe. In later birth cohorts the acceleration in the maternal generation apparently ended. Anthropometric traits at birth (weight, body length, head and chest circumferences) show different patterns of secular changes from 1950 to 1990. According to multiple regression analysis, a temporal trend in the neonate body size might be mainly due to the parallel increase in mother's stature. The contribution of socioeconomic factors to the observed secular growth changes is discussed.