Recessive mutations of SLC26A4 (PDS) are a common cause of Pendred syndrome and non-syndromic deafness in western populations. Although south and east Asia contain nearly one half of the global population, the origins and frequencies of SLC26A4 mutations in these regions are unknown. We PCR amplified and sequenced seven exons of SLC26A4 to detect selected mutations in 274 deaf probands from Korea, China, and Mongolia. A total of nine different mutations of SLC26A4 were detected among 15 (5.5%) of the 274 probands. Five mutations were novel and the other four had seldom, if ever, been identified outside east Asia. To identify mutations in south Asians, 212 Pakistani and 106 Indian families with three or more affected offspring of consanguineous matings were analysed for cosegregation of recessive deafness with short tandem repeat markers linked to SLC26A4. All 21 SLC26A4 exons were PCR amplified and sequenced in families segregating SLC26A4 linked deafness. Eleven mutant alleles of SLC26A4 were identified among 17 (5.4%) of the 318 families, and all 11 alleles were novel. SLC26A4 linked haplotypes on chromosomes with recurrent mutations were consistent with founder effects. Our observation of a diverse allelic series unique to each ethnic group indicates that mutational events at SLC26A4 are common and account for approximately 5% of recessive deafness in south Asians and other populations.A pproximately one half of childhood hearing loss is thought to have a genetic aetiology, the majority of which is non-syndromic and not associated with abnormalities of other organ systems. Estimates from clinical and epidemiological studies suggest that 80-85% of hereditary, non-syndromic, prelingual deafness is autosomal recessive, 15% is autosomal dominant, and a few percent is inherited as an X linked trait or via matrilineal transmission.

Studies of the oceanic and near-shore distributions of Pacific salmon, whose migrations typically span thousands of kilometres, have become increasingly valuable in the presence of climate change, increasing hatchery production and potentially high rates of bycatch in offshore fisheries. Genetics data offer considerable insights into both the migratory routes as well as the evolutionary histories of the species. However, these types of studies require extensive data sets from spawning populations originating from across the species' range. Single nucleotide polymorphisms (SNPs) have been particularly amenable for multinational applications because they are easily shared, require little interlaboratory standardization and can be assayed through increasingly efficient technologies. Here, we discuss the development of a data set for 114 populations of chum salmon through a collaboration among North American and Asian researchers, termed PacSNP. PacSNP is focused on developing the database and applying it to problems of international interest. A data set spanning the entire range of species provides a unique opportunity to examine patterns of variability, and we review issues associated with SNP development. We found evidence of ascertainment bias within the data set, variable linkage relationships between SNPs associated with ancestral groupings and outlier loci with alleles associated with latitude.

In a review of the vertebral angiograms of 300 patients free from disease at the craniovertebral junction, we found atlantoaxial arterial anomalies in 2,3%. These were: 2 cases in which the vertebral artery ran in the spinal canal below C1, 3 cases of duplication of the vertebral artery above and below C1, and 2 cases of origin of the posterior inferior cerebellar artery at C2. Although these arteries ran in the spinal canal between C1 and C2, they never encroached upon the posterior third of the canal. From the survey of another 21 patients having bony abnormalities at the craniovertebral junction, the first type of arterial anomaly described above was seen in 4 patients and associated with failure of segmentation of the embryonic sclerotome such as occipitalization of the atlas or Klippel-Feil syndrome. It is possible to relate the development of these anomalous vessels to malarrangement of the embryonic segmental arteries. Our results indicate that one must be cautious with lateral C1/2 puncture or surgical exposure of the region.

To investigate synchronized annual fluctuation of seed production and its advantage for regeneration at the community level, for nine years (1987–1995) we monitored the flowering, seed production, and seedling emergence of the 16 principal tree species in a temperate deciduous forest, Ogawa Forest Reserve, in central Japan. We found that the species with higher synchronized flowering within a population had larger fluctuation of annual seed production at the population level. The coefficient of concordance of flowering and the coefficient of variation of annual seed production were continuously distributed among species, making it difficult to distinguish masting from nonmasting species. The annual seed production patterns of the 16 species were classified, by cluster analysis, into groups that synchronize their fluctuation of annual seed production. This analysis showed a highly synchronized annual seed production, not only among congeneric species, but also among species of different families. Although our results have some insufficiency of statistical significance, they did show that predator satiation, both in a population and a guild, effectively operated for many species to enhance seed survival at the pre‐dispersal stage. They also showed that pollination efficiency was likely to be operating at the population level for half of the wind‐pollinating species. However, generalist predator satiation at the postdispersal seed stage may not operate in a simple, detectable manner in this species‐rich forest community. It is highly probable that there are combined effects of several factors: limited weather triggers for flowering, common flowering physiology among taxonomically related species, and the ecological advantages at the population and guild levels, may cause multiple species to have synchronized fluctuation patterns of seed production.

To evaluate its usefulness for detection of mutagenicity and oncogenicity of chemicals, the frequency of chromosome aberrations and sister chromatid exchanges (SCE) was examined in cultured Chinese hamster cells exposed to 33 kinds of chemical agents, including 2 aromatic hydrocarbons, 7 amine derivatives, 3 phenols, 6 carboxylic acid derivatives, 4 azo compounds, 7 heterocyclic compounds, and 4 other types of agents. Among them, 7 chemicals, including 5 known oncogens (N-n-butyl-N-nitrosourethan, N-methyl-N-nitrosourea, beta-propiolacton, methylazoxymethanol acetate, and propane sultone) and 2 non-oncogens (potassium sorbate and sodium benzoate) were inducers of aberrations and/or SCE, although the effective doses for the last two agents were considerably higher. The mutagenic activities estimated by chromosome aberrations were not necessarily the same for a given chemical when estimated by SCE. Slightly to moderately increased rates of SCE or aberrations were noticed among the other 26 chemicals. However, these values were usually without a clear dose relationship.