Linked Life Data

12770580

Source:http://linkedlifedata.com/resource/pubmed/id/12770580

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
2003-5-28
pubmed:abstractText
Ticks are obligate blood-feeding parasites that secrete anti-hemostatic components during feeding to enable control of the hemostatic system of the host. Complex interactions at the tick-host interface are an indication of the important role that the host played during tick evolution. The question is to what extent interaction with the host and the environment influences tick evolution. Previously, two isoforms (97% sequence identity) of savignygrin, an alphaIIbbeta3 antagonist, have been described. The presence of both isoforms within 20 random individuals confirmed that these isoforms must be recent gene duplicates. Analysis of the sequence differences between the isoforms shows a Kn/Ks ratio of 1, which indicates neutral selection for the isoforms. However, the biased localization of differences within the 3' end of the genes suggests that concerted evolution acts on the isoforms. Calculation of the divergence date between the isoforms (1.6-5.2 MYA) also indicates purifying selection, as ample time had passed after duplication, for inactivation of one gene copy. We conclude that concerted evolution has functioned to maintain a high copy number of the savignygrins in order for Ornithodoros savignyi to parasitize a wide host range. This contrasts with O. moubata that expresses the savignygrin homolog, disagregin, as a single copy at lower concentration levels and correlates with the confined habitat and consequently narrow host range of O. moubata. Recent "domestication" of O. savignyi due to animal husbandry practices could however, have reduced the selection constraints acting to maintain the gene copies as evidenced by the structural instability of one of the isoforms. Our results suggest that environmental factors and host associations do play an important role in the evolution of anti-hemostatic components in ticks.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0965-1748
pubmed:author
pubmed:issnType
Print
pubmed:volume
33
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
623-9
pubmed:dateRevised
2008-11-21
pubmed:meshHeading
pubmed-meshheading:12770580-Alleles, pubmed-meshheading:12770580-Amino Acid Sequence, pubmed-meshheading:12770580-Animals, pubmed-meshheading:12770580-Base Sequence, pubmed-meshheading:12770580-Environment, pubmed-meshheading:12770580-Evolution, Molecular, pubmed-meshheading:12770580-Gene Duplication, pubmed-meshheading:12770580-Genetic Variation, pubmed-meshheading:12770580-Host-Parasite Interactions, pubmed-meshheading:12770580-Insect Proteins, pubmed-meshheading:12770580-Molecular Sequence Data, pubmed-meshheading:12770580-Phylogeny, pubmed-meshheading:12770580-Platelet Aggregation Inhibitors, pubmed-meshheading:12770580-Protein Isoforms, pubmed-meshheading:12770580-Protein Structure, Secondary, pubmed-meshheading:12770580-Proteins, pubmed-meshheading:12770580-Sequence Alignment, pubmed-meshheading:12770580-Sequence Homology, Amino Acid, pubmed-meshheading:12770580-Species Specificity, pubmed-meshheading:12770580-Ticks
pubmed:year
2003
pubmed:articleTitle
The influence of tick behavior, biotope and host specificity on concerted evolution of the platelet aggregation inhibitor savignygrin, from the soft tick Ornithodoros savignyi.
pubmed:affiliation
Department of Biochemistry, University of Pretoria, Pretoria 0002, South Africa. ben.mans@bioagric.up.ac.za
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't