Strychnos 1990 - 2004 - Crops for the Future
Strychnos 1990 - 2004 - Crops for the Future
Strychnos 1990 - 2004 - Crops for the Future
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Author<br />
Title<br />
Year<br />
Source title<br />
Reference<br />
Baimai, V., J. Phinchongsakuldit and C. Sumrandee<br />
Cytological evidence <strong>for</strong> a complex of species within <strong>the</strong> taxon Bactrocera tau (Di<br />
2000<br />
Biological Journal of <strong>the</strong> Linnean Society<br />
69(3): 399-409<br />
Abstract<br />
Analysis of mitotic karyotypes of wild specimens of larvae of <strong>the</strong> Bactrocera tau-like fruit flies<br />
(Diptera: Tephritidae) in Thailand has revealed seven distinct chromosome <strong>for</strong>ms, based on <strong>the</strong><br />
amount and distribution of heterochromatin in sex chromosomes and autosomes. Such cytological<br />
differences are perfectly correlated with morphological observations and molecular genetics data.<br />
These findings clearly suggest that B. tau is a cluster of at least seven closely related species<br />
temporarily designated as species A (=B. tau), B, C, D, E, F and G. On <strong>the</strong> basis of <strong>the</strong> gross<br />
quantity of heterochromatin accumulation in <strong>the</strong> genome, three groups of mitotic karyotypes can be<br />
recognized. Group 1 comprises species A and E. Species E specifically occurs only in fruits of<br />
<strong>Strychnos</strong> thorelii while species A attacks many kinds of host plants. Group 2 contains species B, F<br />
and G. Species B has been found only in Siphonodon celastrineus fruit, whereas species F and G<br />
attack <strong>the</strong> same host species, <strong>the</strong> medically important plant, Hydnocarpus an<strong>the</strong>lminthicus, albeit in<br />
different localities. Group 3 includes species C and D, each of which comprises larger amounts of<br />
pericentric heterochromatin in all chromosomes than <strong>the</strong> o<strong>the</strong>r two groups. Hence, <strong>the</strong>se two species<br />
are cytologically remote from those of groups 1 and 2. Species C and D occur allopatrically but <strong>the</strong>y<br />
attack <strong>the</strong> same host plant species, Momordica cochinchinensis. Thus, genetic differentiation at <strong>the</strong><br />
chromosomal level to specific host plant species and geographic isolation seem to play an important<br />
role in speciation of members of <strong>the</strong> B, tau complex. (C) 2000 The Linnean Society of London.