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Selected AbstractsCaddisfly diapause aggregations facilitate benthic invertebrate colonizationJOURNAL OF ANIMAL ECOLOGY, Issue 6 2003Declan J. McCabe Summary 1We used natural and manipulative field experiments to examine the effects of caddisfly (Trichoptera) diapause aggregations on benthic macroinvertebrates communities in a Vermont river. 2Natural substrates with aggregations of Neophylax and Brachycentrus (Trichoptera: Uenoidae and Brachycentridae) had higher species richness than did substrates lacking aggregations. Aggregations of caddisfly cases added to artificial substrates (bricks) also accumulated greater abundance, species density (number of species per unit area), and species richness (number of species per standard number of individuals) than did control bricks. 3Low-density, uniformly spaced, Brachycentrus cases accumulated higher species density and species richness than did an equivalent density of clumped cases. Similarly, empty Neophylax cases accumulated higher diversity than did cases still occupied by Neophylax pupae. 4Although natural substrates had higher species richness than artificial substrates, substrate type did not change qualitatively the effect of caddisfly aggregations on species richness. 5We subsampled individuals randomly from aggregations and control surfaces to provide an estimate of species richness unbiased by abundance. Expected species richness was higher in aggregations than on control surfaces. These results suggest that caddisfly aggregations increase species density by altering the shape of the species,abundance distribution as well as by accumulating individuals and species passively. 6We conclude that caddisfly diapause aggregations increase habitat complexity and facilitate colonization of other benthic species. [source] Association of single nucleotide polymorphisms in the endothelial differentiation sphingolipid G-protein-coupled receptor 1 gene with marbling in Japanese Black beef cattleANIMAL GENETICS, Issue 2 2009T. Yamada Summary Marbling defined by the amount and distribution of intramuscular fat, so-called Shimofuri, is an economically important trait of beef cattle in Japan. The endothelial differentiation sphingolipid G-protein-coupled receptor 1 (EDG1) gene, involved in blood vessel formation, has been previously shown to be expressed at different levels in musculus longissimus muscle between low-marbled and high-marbled steer groups. It is located within the genomic region of a quantitative trait locus for marbling, and thus was considered as a positionally functional candidate for the gene responsible for marbling. In this study, two single nucleotide polymorphisms (SNPs) in the 5, untranslated region (UTR) and the 3, UTR of EDG1, referred to as c. - 312A>G and c.*446G>A, respectively, were detected between the two steer groups. The two SNPs were associated with the predicted breeding value for beef marbling standard number by analyses using a population of Japanese Black beef cattle. The effect of genotypes at each of the SNPs on the predicted breeding value for subcutaneous fat thickness was not statistically significant (P > 0.05). Reporter gene assays revealed no significant differences in gene expression between alleles at each of the SNPs. These findings suggest that EDG1 SNPs, although they may not be regarded as a causal mutation, may be useful for effective marker-assisted selection to increase the levels of marbling in Japanese Black beef cattle. [source] Association of a single nucleotide polymorphism in ribosomal protein L27a gene with marbling in Japanese Black beef cattleANIMAL SCIENCE JOURNAL, Issue 6 2009Takahisa YAMADA ABSTRACT Marbling, defined by the amount and distribution of intramuscular fat, is an economically important trait of beef cattle in Japan. The c2-11#2 expressed sequence tag (EST) has been previously shown to possess expression difference in musculus longissimus muscle between low-marbled and high-marbled steer groups, and to be located within genomic region of a quantitative trait locus for marbling. Thus, the ribosomal protein L27a (RPL27A) gene containing the c2-11#2 EST sequence was considered as a positional candidate for the gene responsible for marbling. In the present study, a single nucleotide polymorphism (SNP) in the promoter region of the RPL27A, referred to as g.3109537C>T, was detected between the 2 steer groups. The SNP was associated with the predicted breeding value for beef marbling standard number by the analyses using Japanese Black beef cattle population. The effect of genotypes of the SNP on the predicted breeding value for subcutaneous fat thickness was not statistically significant. These findings suggest that the RPL27A SNP may be useful for effective marker-assisted selection to increase the levels of marbling in Japanese Black beef cattle. [source] Novel SNP in 5, flanking region of EDG1 associated with marbling in Japanese Black beef cattleANIMAL SCIENCE JOURNAL, Issue 4 2009Takahisa YAMADA ABSTRACT Marbling, defined by the amount and distribution of intramuscular fat, is an economically important trait of beef cattle in Japan. The endothelial differentiation, sphingolipid G-protein-coupled receptor, 1 (EDG1) gene has been considered as a positional functional candidate for the gene responsible for marbling. We have recently reported that 2 single nucleotide polymorphisms (SNPs), c.-312A>G in the 5, untranslated region (UTR) and c.*446G>A in the 3, UTR in EDG1 were associated with marbling in Japanese Black beef cattle, but this was not functional and a causal mutation for marbling. In the present study, we detected 2 novel SNPs, referred to as g.1475435G>A and g.1471620G>T, in the 5, flanking region of the EDG1 between low-marbled and high-marbled steer groups, which were previously shown to have EDG1 expression differences in musculus longissimus muscle. The g.1475435G>A SNP seemed not to segregate in Japanese Black beef cattle. The g.1471620G>T SNP was associated with the predicted breeding value for beef marbling standard number by the analyses using Japanese Black beef cattle population. Based on these findings, we hypothesized that the g.1471620G>T SNP might have an impact on EDG1 expression and also marbling. [source] | ||||||||||