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Application of the principal component analysis (PCA) to the ecological study of an artificial environment: the tunny-fishing net of Camogli (Ligurian Sea).

The management of the marine environment and resource exploitation depend on the knowledge of both water conditions and ecological relationships between organisms. In the framework of fishing problems, an adequate food availability is important in order to allow maintaining and growth of fish stocks. The tunny-fishing of Camogli, owing to the coco-fibre texture of its net, can improve the trophic resources allowing the settlement of organisms eaten by fish. The distribution and composition of settled organisms was studied during the campaign 1988 by microscopical methods. The results have been elaborated by using multivariate (PCA) methods. Foraminifers, ciliates, hydroids, nematodes and copepods were the mainly observed groups. Their variations with season and depth and the relationships with caught fish species are presented. The elaboration of data by PCA allowed an easy and complete interpretation of the obtained complex data set showing the existence of a "rope" and of a "depth" effect.

Animals↗
PubMed2004

[Principal component analysis of Y-chromosome haplotype distribution in 18 ethnic groups in Yunnan Province].

Based on the historical records, 18 of the 26 ethnic groups in Yunnan Province are the descendant populations of three ancient tribes, Bai-Yue, Bai-Pu and Di-Qiang, linguistically belonging to the Daic, Austro-Asiatic and Tibeto-Burman, respectively. In order to trace the origins of these native ethnic groups, a total of 13 East Asian specific Y-chromosome biallelic markers were used to study the genetic structure of 20 local populations covering all the 18 ethnic groups in Yunnan Province. Haplotypes were analysis by PCR-RFLP method. Our results showed that H11 and H12 were the predominant haplotypes in the descendant populations of Bai-Yue tribe. H5, H6 and H8 were the dominant haplotypes in Di-Qiang descendants, and the frequencies of H6, H8 and H11 were very high in the descendant populations of Bai-Pu. To investigate relationships among 20 populations, a three dimensional PC analysis were performed based on the distribution of the 13 haplotypes. All populations were divided into two clusters in the PC plot. The first cluster was mainly composed by the descendant populations of Bai-Yue, and the second one was mainly composed by the descendants of Di-Qiang tribe. This result indicated that Bai-Yue and Di-Qiang's paternal lineage had different origins, which was in agreement with the historical documents and linguistic classification.

Asian People↗