Conservation of a highly repeated DNA family of Aedes albopictus among mosquito genomes (Diptera: Culicidae)

Abstract

The genomic organization and chromosomal localization of a cloned 0.79-kb highly repeated DNA fragment, H-115, isolated from Aedes albopictus has been examined. The cloned fragment is a part of a larger unit of 1.86 kb that is tandemly repeated in the Ae. albopictus genome. The H-115 family of sequences are located at the intercalary position on chromosome 1 in Ae. albopictus. Similar patterns of in situ and Southern blot hybridization results are obtained in Ae. aegypti, Ae. seatoi, Ae. flavopictus, Ae. polynesiensis, Ae. Alcasidi, and Ae. katherinensis. The H-115 sequences are widely conserved in Culicidae and are found in Haemagogus equinus, Tripteroides bambusa, and Anopheles quadrimaculatus by hybridization under high stringency conditions. The H-115 sequences are also tandemly repeated in Hg. equinus with a monomer unit of 1.86 kb and in Tp. bambusa with a slightly diverged monomer unit of 1.90kb. In Anopheles quadrimaculatus, the H-115 sequences are dispersed throughout the genome. Partial sequence analysis shows that the H-115 insert is 62% AT and contains two perfect inverted repeats and numerous perfect direct repeats. The occurrence of inverted repeats with potential to form intrastrand palindromic structure suggests that the H-115 family of sequences may be involved in chromatin condensation.