As a base for human transcriptome and functional genomics, we created the "full-length long Japan" (FLJ) collection of sequenced human cDNAs. We determined the entire sequence of 21,243 selected clones and found that 14,490 cDNAs (10,897 clusters) were unique to the FLJ collection. About half of them (5,416) seemed to be protein-coding. Of those, 1,999 clusters had not been predicted by computational methods. The distribution of GC content of nonpredicted cDNAs had a peak at ∼58% compared with a peak at ∼42%for predicted cDNAs. Thus, there seems to be a slight bias against GC-rich transcripts in current gene prediction procedures. The rest of the cDNAs unique to the FLJ collection (5,481) contained no obvious open reading frames (ORFs) and thus are candidate noncoding RNAs. About one-fourth of them (1,378) showed a clear pattern of splicing. The distribution of GC content of noncoding cDNAs was narrow and had a peak at ∼42%, relatively low compared with that of protein-coding cDNAs.
A newly developed DNA microarray was applied to identify mitochondrial (mt) DNA haplotypes of more than 2200 chum salmon in the Bering Sea and North Pacific Ocean in September 2002 and also 2003, when the majority of maturing fish were migrating toward their natal river. The distribution of haplotypes occurring in Asian and North American fish in the surveyed area was similar in the 2 years. A conditional maximum likelihood method for estimation of stock compositions indicated that the Japanese stocks were distributed mainly in the north central Bering Sea, whereas the Russian stocks were mainly in the western Bering Sea. The North American stocks were abundant in the North Pacific Ocean around the Aleutian Islands. These results indicate that the Asian and North American stocks of chum salmon are nonrandomly distributed in the Bering Sea and the North Pacific Ocean, and further the oligonuleotide DNA microarray developed by us has a high potential for identification of stocks among mixed ocean aggregates of high-seas chum salmon.
For use in genetic stock identification, we developed an oligonucleotide (DNA) microarray hybridization method for rapid and accurate detection of nucleotide sequence variations in 20 previously identified variable nucleotide sites in about 500 bp within the 5' half of the control region of mitochondrial DNA of chum salmon (Oncorhynchus keta). The method includes immobilization of synthesized oligonucleotides containing respective polymorphic sites on a glass slide precoated with polycarbodiimide resin, a 2-hour hybridization with DNA microarray of biotinylated polymerase chain reaction fragments spanning the 5' variable portion followed by short washing, and visualization of hybridization signals by conventional ABC method and scanner-assisted computation of signal intensity on a computer. The entire process of hybridization and detection was completed within 4 hours. The resulting DNA microarray could detect all of the single nucleotide mutations and therefore could be used to identity the sequence variations defining 30 mtDNA haplotypes of chum salmon as revealed previously by nucleotide sequence analysis.
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