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751.
752.
S Togashi R Ueda M Takahisa M Mikuni K Kondo T Miyake 《The Japanese Journal of Genetics》1992,67(4):291-297
Drosophila yakuba, a member of melanogaster subgroup being free of P element, acquired resistance to an antibiotic neomycin by the transformation utilizing P element. In this species, the transformation frequency was comparable to that of D. melanogaster. Further, the occurrence of 8 base pairs duplication upon the insertion of the element was confirmed. These facts suggest that the P element could be inserted into the genome in the same manner, even in D. yakuba. Any consensus for preferential insertion could not be found on the nucleotide sequence as in D. melanogaster. However, it is noticeable that a series of the short palindromic stretches was common around the insertion sites in both species. It suggests that a structural feature of DNA plays a role as a landmark for P element insertion. 相似文献
753.
754.
Masahiro Nakaoka Norihiko Ito Tomoko Yamamoto Takehiro Okuda Takashi Noda 《Ecological Research》2006,21(3):425-435
Factors and processes affecting community structures operate at various spatial and temporal scales. We analyzed how similarities
of rocky intertidal assemblages vary at different spatial scales using a nested, hierarchical sampling design. Intertidal
assemblages consisting of algae, sessile animals, and mobile animals were censused on five rock walls at each of five shores
chosen within each of six regions along the Pacific coast of Japan, encompassing 1,800 km of coastlines. Based on this sampling
design, similarities in assemblages were calculated using both qualitative (presence/absence) and quantitative (percent cover
and density) data, and compared at three spatial levels: (1) rock level (the finest spatial scale, encompassing several to
hundreds of meters), (2) shore level (the intermediate spatial scale, encompassing several to tens of kilometers), and (3)
region level (the broadest spatial scale, encompassing hundreds to thousands of kilometers). Cluster analysis showed that
assemblages were categorized into distinct regional groups except for the two southern regions, but they did not separate
clearly from each shore. A nested analysis of similarities revealed significant variation in similarities among regions and
among shores within each region, with the former showing greater variation. Similarity was negatively correlated with geographic
distance at the regional level but not at the shore or the rock levels. At the regional level, similarity decreased more rapidly
with distance for mobile animals than sessile organisms. The analyses highlighted the importance of broad-scale abiotic/biotic
factors such as oceanic current conditions and biogeographic factors in determining observed patterns in similarity of rocky
intertidal assemblages. 相似文献
755.
To compare the nutrient economy of woody plants at timberline of Mt. Fuji, seasonal changes in nitrogen content in leaves
were examined. There was remarkable difference in seasonal changes in leaf nitrogen content betweenAlnus maximowiczii and other deciduous trees at same habitat.A. maximowiczii scarcely withdrew the leaf nitrogen to woody part during the shedding period, while the other species withdrew about half
of the leaf nitrogen to woody part. 相似文献