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171.
172.
Mirjam MJ Jacobs Ronald G van den Berg Vivianne GAA Vleeshouwers Marcel Visser Rolf Mank Mariëlle Sengers Roel Hoekstra Ben Vosman 《BMC evolutionary biology》2008,8(1):145
Background
The secondary genepool of our modern cultivated potato (Solanum tuberosum L.) consists of a large number of tuber-bearing wild Solanum species under Solanum section Petota. One of the major taxonomic problems in section Petota is that the series classification (as put forward by Hawkes) is problematic and the boundaries of some series are unclear. In addition, the classification has received only partial cladistic support in all molecular studies carried out to date. 相似文献173.
WS Watkins R Thara BJ Mowry Y Zhang DJ Witherspoon W Tolpinrud MJ Bamshad S Tirupati R Padmavati H Smith D Nancarrow C Filippich LB Jorde 《BMC genetics》2008,9(1):1-17
Background
Major population movements, social structure, and caste endogamy have influenced the genetic structure of Indian populations. An understanding of these influences is increasingly important as gene mapping and case-control studies are initiated in South Indian populations.Results
We report new data on 155 individuals from four Tamil caste populations of South India and perform comparative analyses with caste populations from the neighboring state of Andhra Pradesh. Genetic differentiation among Tamil castes is low (RST = 0.96% for 45 autosomal short tandem repeat (STR) markers), reflecting a largely common origin. Nonetheless, caste- and continent-specific patterns are evident. For 32 lineage-defining Y-chromosome SNPs, Tamil castes show higher affinity to Europeans than to eastern Asians, and genetic distance estimates to the Europeans are ordered by caste rank. For 32 lineage-defining mitochondrial SNPs and hypervariable sequence (HVS) 1, Tamil castes have higher affinity to eastern Asians than to Europeans. For 45 autosomal STRs, upper and middle rank castes show higher affinity to Europeans than do lower rank castes from either Tamil Nadu or Andhra Pradesh. Local between-caste variation (Tamil Nadu RST = 0.96%, Andhra Pradesh RST = 0.77%) exceeds the estimate of variation between these geographically separated groups (RST = 0.12%). Low, but statistically significant, correlations between caste rank distance and genetic distance are demonstrated for Tamil castes using Y-chromosome, mtDNA, and autosomal data.Conclusion
Genetic data from Y-chromosome, mtDNA, and autosomal STRs are in accord with historical accounts of northwest to southeast population movements in India. The influence of ancient and historical population movements and caste social structure can be detected and replicated in South Indian caste populations from two different geographic regions. 相似文献174.
Stavropoulos-Kalinoglou A Metsios GS Panoulas VF Douglas KM Nevill AM Jamurtas AZ Kita M Koutedakis Y Kitas GD 《Arthritis research & therapy》2008,10(3):R59
Introduction
Rheumatoid arthritis (RA) is associated with altered metabolism leading to muscle wasting. In the general population, cigarette smoking is known to affect body composition by reducing fat and inhibiting muscle synthesis. Even though smoking has been implicated in the pathophysiology and progression of RA, its possible effects on body composition of such patients have not been studied. This cross-sectional study aimed to identify potential associations of smoking with body weight and composition of RA patients. 相似文献175.
Chloe?KB?Mortimer Tansy?M?Peters Saheer?E?Gharbia Julie?MJ?Logan Catherine?ArnoldEmail author 《BMC microbiology》2004,4(1):31
Background
The fliC and fljB genes in Salmonella code for the phase 1 (H1) and phase 2 (H2) flagellin respectively, the rfb cluster encodes the majority of enzymes for polysaccharide (O) antigen biosynthesis, together they determine the antigenic profile by which Salmonella are identified. Sequencing and characterisation of fliC was performed in the development of a molecular serotyping technique. 相似文献176.
Understanding complex cellular processes requires methods for specifically perturbing protein function in a temporally defined fashion. In recent years a variety of chemical tools have been used to study the cytoskeleton and cell division, protein trafficking, and the destruction of proteins by the ubiquitin-proteasome system. The ability to use combinations of reversible inhibitors is proving to be especially helpful in dissecting complex cellular events. Furthermore, the identification of novel inhibitors through unbiased screening approaches is revealing novel drugable steps in important cellular pathways. 相似文献
177.
178.
Evolution of alcohol dehydrogenase genes in peonies (Paeonia): phylogenetic relationships of putative nonhybrid species 总被引:11,自引:0,他引:11
Alcohol dehydrogenase genes were amplified by PCR, cloned, and sequenced
from 11 putative nonhybrid species of the angiosperm genus Paeonia.
Sequences of five exons and six intron regions of the Adh gene were used to
reconstruct the phylogeny of these species. Two paralogous genes, Adh1A,
and Adh2, were found; an additional gene, Adh1B, is also present in section
Moutan. Phylogenetic analyses of exon sequences of the Adh genes of Paeonia
and a variety of other angiosperms imply that duplication of Adh1 and Adh2
occurred prior to the divergence of Paeonia species and was followed by a
duplication resulting in Adh1A and Adh1B. Concerted evolution appears to be
absent between these paralogous loci. Phylogenetic analysis of only the
Paeonia Adh exon sequences, positioning the root of the tree between the
paralogous genes Adh1 and Adh2, suggests that the first evolutionary split
within the genus occurred between the shrubby section Moutan and the other
two herbaceous sections Oneapia and Paeonia. Restriction of Adh1B genes to
section Moutan may have resulted from deletion of Adh1B from the common
ancestor of sections Oneapia and Paeonia. A relative-rate test was designed
to compare rates of molecular change among lineages based on the divergence
of paralogous genes, and the results indicate a slower rate of evolution
within the shrubby section Moutan than in section Oneapia. This may be
responsible for the relatively long branch length of section Oneapia and
the short branch length between section Moutan and the other two sections
found on the Adh, ITS (nrDNA), and matK (cpDNA) phylogenies of the genus.
Adh1 and Adh2 intron sequences cannot be aligned, and we therefore carried
out separate analyses of Adh1A and Adh2 genes using exon and intron
sequences together. The Templeton test suggested that there is not
significant incongruence among Adh1A, ITS, and matK data sets, but that
these three data sets conflict significantly with Adh2 sequence data. A
combined analysis of Adh1A, ITS, and matK sequences produced a tree that is
better resolved than that of any individual gene, and congruent with
morphology and the results of artificial hybridization. It is therefore
considered to be the current best estimate of the species phylogeny.
Paraphyly of section Paeonia in the Adh2 gene tree may be caused by longer
coalescence times and random sorting of ancestral alleles.
相似文献
179.
S J Hathaway M J Fregly K M Wilson P E Papanek W N Henley 《Proceedings of the Society for Experimental Biology and Medicine. Society for Experimental Biology and Medicine (New York, N.Y.)》1986,183(1):92-98
Chronic (72 days) administration of deoxycorticosterone acetate (DOCA), with or without saline as the sole drinking fluid, depleted atria of rats of their diuretic and natriuretic activities. Chronic ingestion of saline as the sole drinking fluid did not affect the diuretic, natriuretic, and kaliuretic activities of atria compared with those of rats receiving water to drink. Since systolic blood pressure of the DOCA-treated group did not differ significantly from that of the untreated control group, the decrease in potency of atrial extract from DOCA-treated rats most likely occurred in response to increases in extracellular and vascular volumes. The ability of DOCA to decrease diuretic and natriuretic activities of atria was dose dependent. The decreased activities of the atria of DOCA-treated rats could reflect an increased production and turnover of atrial natriuretic factor. Additional studies revealed an increased diuretic and natriuretic responsiveness of DOCA-treated recipients to atrial extract from untreated rats. Thus, the results of these studies suggest that chronic treatment with DOCA reduced the natriuretic and diuretic potencies of atrial extract and increased renal responsiveness to it. 相似文献
180.
Amino acid sequence versus morphological data and the interordinal relationships of mammals 总被引:2,自引:0,他引:2
To a large extent, the mutual affinities of the mammalian orders continue
to puzzle systematists, even though comparative anatomy and amino acid
sequencing offer a massive data base from which these relationships could
potentially be adduced. In the present paper the consistency index--the
number of character states less the number of characters in a data set,
divided by the total number of changes in the character states on a
cladogram--was used to examine the relative resolving powers of recently
published morphological and molecular- sequence data. Consistency indices
were calculated for previously published alpha crystallin A chain and
myoglobin amino acid-sequence cladograms and for four original amino
acid-sequence cladograms (alpha crystallin A, myoglobin, and alpha and beta
hemoglobin); these were found to be comparable to the consistency indices
of morphologically based cladograms. Qualitative comparisons between the
morphologically based and molecularly based trees were also made; only
moderate congruence between the two was observed. Moreover, there was a
general lack of congruence between the cladograms specified by each of the
four proteins. Amino acid-sequence and morphological data agreed on the
placement of edentates as an early eutherian offshoot and on the grouping
of hyracoids, proboscideans, and sirenians. Otherwise there was only
limited congruence: morphology strongly supported the grouping of
lagomorphs and rodents and the alliance of pholidotes and edentates, but
sequence analyses did not. The placement of tubulidentates differed widely
among proteins. Morphology indicated the close association of sirenians
with proboscideans; proteins suggested a pairing of sirenians with
hyracoids. Sequence data did not identify many (morphologically
well-diagnosed) orders as monophyletic (e.g., Lagomorpha).(ABSTRACT
TRUNCATED AT 250 WORDS)
相似文献