Home  About us  Contact
 

Arctic Populations (arctic + population)

Distribution by Scientific Domains
Life Sciences100%

Selected Abstracts

Relationships of Palearctic and Nearctic ,glacial relict'Myoxocephalus sculpins from mitochondrial DNA data

MOLECULAR ECOLOGY, Issue 11 2003
Tytti Kontula
Abstract The relationships among Myoxocephalus quadricornis complex fish from Arctic coastal waters and from ,glacial relict' populations in Nearctic and Palearctic postglacial lakes were assessed using mtDNA sequence data (1978 bp). A principal phylogeographical split separated the North American continental deepwater sculpin (M. q. thompsonii) from a lineage of the Arctic marine and North European landlocked populations of the fourhorn sculpin (M. q. quadricornis). The North American continental invasion took place several glaciation cycles ago in the Early-to-Middle Pleistocene (0.9% sequence divergence); the divergence of the European and Arctic populations was somewhat later (0.5% divergence). The Nearctic-Palearctic freshwater vicariance in Myoxocephalus, however, appears clearly younger than in similarly distributed ,glacial relict' crustacean taxa; the phylogeographical structure is more similar to that in other northern Holarctic freshwater fish complexes. [source]

The health of Arctic populations: Does cold matter?

AMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 1 2010
T. Kue Young
The objective of the study was to examine whether cold climate is associated with poorer health in diverse Arctic populations. With climate change increasingly affecting the Arctic, the association between climate and population health status is of public health significance. The mean January and July temperatures were determined for 27 Arctic regions based on weather station data for the period 1961,1990 and their association with a variety of health outcomes assessed by correlation and multiple linear regression analyses. Mean January temperature was inversely associated with infant and perinatal mortality rate, age-standardized mortality rate from respiratory diseases, and age-specific fertility rate for teens and directly associated with life expectancy at birth in both males and females, independent of a variety of socioeconomic, demographic, and health care factors. Mean July temperature was also associated with infant mortality and mortality from respiratory diseases, and with total fertility rate. For every 10°C increase in mean January temperature, the life expectancy at birth among males increased by about 6 years and infant mortality rate decreased by about 4 deaths/1,000 livebirths. Cold climate is significantly associated with higher mortality and fertility in Arctic populations and should be recognized in public health planning. Am. J. Hum. Biol., 2010. © 2009 Wiley-Liss, Inc. [source]

Molecular phylogeny of the Sphaerophorus globosus species complex

CLADISTICS, Issue 3 2003
Filip Högnabba
The Sphaerophorus globosus complex (Lecanorales, lichenized Ascomycota) shows a large morphological variation, and three relatively distinct morphotypes can be distinguished in parts of the distribution area. Here, we utilize a multigene-based maximum-parsimony approach (nITS+ LSU rDNA, mtSSU rDNA, ,-tubulin, and actin) to investigate whether these morphotypes constitute distinct species. The results show that there are at least two well-supported monophyletic groups that we interpret as phylogenetic species within the S. globosus complex. These species do not completely correspond to the predefined morphotypes. One group, an apparently undescribed species, contains noncoralloid specimens from the North American Pacific Northwest. The other group, S. globosus, consists of two well-supported monophyletic groups: one contains coralloid epiphytic specimens from the North American Pacific Northwest that are morphologically indistinguishable from epiphytic specimens from Europe and are presently interpreted as belonging to the same species and the other is morphologically variable and contains terrestrial specimens from Europe, North America, and southernmost South America and coralloid epiphytic and epilithic specimens from Europe. The results suggest that the population in southernmost South America originated by long-distance dispersal from arctic populations in the Northern Hemisphere. [source]