Karyotypes of Chironomus Meigen (Diptera: Chironomidae) species from Africa

Wolfgang F Wülker,A Istomina,Iya Kiknadze

doi:10.3897/compcytogen.v5i1.975

Abstract

The karyotypes of six African Chironomus species (Chironomus alluaudi Kieffer, 1913, Chironomus transvaalensis Kieffer, 1923, Chironomus sp. Nakuru, Chironomus formosipennis Kieffer, 1908, Chironomus prope pulcher Wiedemann, 1830, Chironomus sp. Kisumu) were investigated; four of these karyotypes were described for the first time (Chironomus sp. Nakuru, Chironomus formosipennis, Chironomus prope pulcher, Chironomus sp. Kisumu). Of the six Chironomus karyotypes, three had “pseudothummi” cytocomplex chromosome arms combinations AE CD BF G (Chironomus alluaudi, Chironomus transvaalensis, Chironomus sp. Nakuru), two had “thummi”cytocomplex arms combinations AB CD EF G (Chironomus formosipennis, Chironomus prope pulcher), and one had “parathummi”armcombinations AC BF DE G (Chironomus sp. Kisumu). Thus, three of the ten main cytocomplexes known were detected in Africa. Detailed photomaps of all chromosome arms, with the exception of arms B and G, were prepared for the karyotypes of Chironomus alluaudi, Chironomus transvaalensis, Chironomus sp. Nakuru, Chironomus prope pulcher; the karyotypes of Chironomus formosipennis, Chironomus sp. Kisumucould only be fragmentarily mapped.Endemic African banding sequences were characteristic for most of the chromosomal arms in all species studied. However, basic sequences, which can be present in different Chironomus species on different continents (Wülker, 1980; Kiknadze et al. 2008), were also detected also in several African species (Chironomus alluaudi, Chironomus sp. Nakuru, and Chironomus formosipennis). The banding sequences of African species studied allow discussion of the derivation of modern banding patterns from hypothetical species, living before separation of cytocomplexes and continents.

Highlights

As shown by cytogenetic analysis of chromosomal evolution, the divergence of animal karyotypes during speciation was mainly mediated by para- and pericentric inversions, altering the gene orders in linkage groups (Dobzhansky 1970, White 1977, King 1993, Zdobnov et al 2002)
Kisumu) were investigated; four of these karyotypes were described for the first time
Forth instar larvae of African Chironomus species were used for karyotype study. 35 years ago, one of us (W.W.) had the opportunity to visit Kenya (22.12.1975– 16.01.1976)

Summary

Introduction

As shown by cytogenetic analysis of chromosomal evolution, the divergence of animal karyotypes during speciation was mainly mediated by para- and pericentric inversions, altering the gene orders in linkage groups (Dobzhansky 1970, White 1977, King 1993, Zdobnov et al 2002). Comparison of banding sequences between species from different cytocomplexes have shown that karyotypes can include species-specific sequences and so called basic sequences, common to more than one cytocomplex and in more than one continent. Such basic sequences were probably present before the separation of species and cytocomplexes (Keyl 1962, Wülker 1980). Basic sequences, common for different continents were found in karyotypes of some species in addition to the endemic sequences Such basic sequences were noted in two African Chironomus species The presence of further basic banding sequences in the karyotypes of African Chironomus species was discovered, along with endemic continent-specific (Ethiopian region) sequences.

Material and methods

Results

Discussion