Population cytogenetics of Chironomus circumdatus Kieffer, 1921 (Diptera, Chironomidae) from Thailand

Abstract

The objectives of this study were to explore cytogenetic variation and the role of chromosomal change on local adaptation and genetic differentiation of Chironomus circumdatus Kieffer from Thailand. A total of 1,505 larvae from 24 populations were examined cytologically. Twelve chromosomal inversions were found and most of these (9 of 12) were rare inversions. All populations were in Hardy-Weinberg equilibrium. Significant association (P < 0.001) between the A2 and B5 inversions was detected in one population. Population genetic structure analysis indicated significant genetic differentiation between populations (F (ST) = 0.037, P < 0.001). Geographic distance was the principal factor limiting gene flow between populations. Nei's modified genetic distance (D (A)) between populations ranged from 0.001 to 0.011 with an average of 0.003. An UPGMA population phenogram depicting relationship between populations based on D (A) values revealed three groups of populations, group I, II and III each characterized by different inversions/inversion frequencies. Significant correlation of inversion C3 and water temperature suggested that this inversion might have a role to play on adaptation to high temperature habitat. However, if detection of significant population subdivision and relationship between genetic and geographic distance are taken into account, relationship between C3 and water temperature will also be due to the effect of migration/drift alone without the effect of selection.

Cytogenetics of the Black Fly Simulium aureohirtum Brunetti from Thailand

“…The value of F ST was similar to those of S. exiguum in Ecuador (F ST ϭ0.083) (Charalambous et al 2005) but much lower than those of S. nakhonense (F ST ϭ0.651) (Pramual 2006), Prosimulium fuscum (F ST ϭ0.421) and Simulium decorum (F ST ϭ0.622) . A significant relationship between the level of genetic differentiation (D A values) and geographic distance (Km) between populations (rϭ0.497, pϭ0.004) suggests that gene flow was limited by geographic distance.…”

“…Stalker (1980) found that the standard sequence of the chromosomes of Drosophila melanogaster was involved in adaptation to cold temperature. Pramual et al (2008) found an association between inversions and water temperature in Chironomus circumdatus. Etges et al (2006) found that frequency shifts in the chromosome inversions in D. robusta was a response to recent climatic change.…”

“…Sella et al 2004, Pramual et al 2008. Because they present at very low frequency and restricted in a particular population rare inversions are likely to originate recently (Aulard et al 2002, Pramual et al 2008.…”

Chromosomal polymorphism in mammals: an evolutionary perspective

“…While population cytogenetic studies exist for a number of other animals (sparrows: Thomas et al ., , and references therein; grasshoppers: Shaw et al ., ; midges: Pramual et al ., ; water beetles: Aradottir & Angus, ; butterflies: Lukhtanov et al ., ), they remain scarce for mammals where data on karyotypic polymorphisms are surprisingly rare (Coghlan et al ., ), thus limiting our understanding of chromosome‐associated evolutionary processes. In fact, well‐sampled model mammalian taxa that are conventionally recognized as being highly polymorphic usually exist as complexes of (sub)species/races where various cytotypes correspond to geographically fixed karyotypes (i.e.…”

Whole issue

“…Recently, Pramual et al (2008) noted the synonymy of Chironomus plumatisetigerus with Chironomus circumdatus, based on the information of the web page of Martin (2007). That web page is not a recognised publication and, further, the synonymy is not indicated in either the title or abstract of the paper.…”