Abstract:
:The two internal transcribed spacers (ITS1 and ITS2) of rDNA of three members of the Ixodes ricinus "complex" (Acari: Ixodidae) were sequenced. Sequence variation was assessed for the North American species I. scapularis, I. dammini, and I. pacificus at three levels: within individual/population, between individuals of different geographic origin within a species, and between species. Both spacers are highly variable, particularly with regard to small deletions and additions which may arise via replication slippage. Homogenization of rDNA multigene arrays for particular sequence variants appears to occur at a relatively rapid rate, since I. pacificus sequences differ from the others at numerous invariant sites, facilitating the use of these sequences to assess sibling species relationships. Based on maximum parsimony and two distance methods (unweighted pair-group with arithmetic means and neighbor-joining), sequence variation in ITS1 and ITS2 suggests that I. scapularis and I. dammini are not distinct species and that even individuals from geographically isolated locations are very similar. Individuals from geographically separated populations of I. pacificus appear to be relatively less closely related to each other but distinct from those of I. scapularis/dammini. In I. scapularis/dammini, diversity within and between individuals from geographic populations contributed equally to total sequence diversity.
journal_name
Proc Natl Acad Sci U S Aauthors
Wesson DM,McLain DK,Oliver JH,Piesman J,Collins FHdoi
10.1073/pnas.90.21.10221subject
Has Abstractpub_date
1993-11-01 00:00:00pages
10221-5issue
21eissn
0027-8424issn
1091-6490journal_volume
90pub_type
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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journal_title:Proceedings of the National Academy of Sciences of the United States of America
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