Karyotypes, constitutive heterochromatin, and genomic DNA values in the blowfly generaChrysomya,Lucilia, andProtophormia(Diptera: Calliphoridae)

Abstract

The karyotypes and C-banding patterns of Chrysomya species C. marginalis, C. phaonis, C. pinguis, C. saffranea, C. megacephala (New Guinean strain), Lucilia sericata, and Protophormia terraenovae are described. All species are amphogenic and have similar chromosome complements (2n = 12), including an XY-XX sex-chromosome pair varying in size and morphology between species. Additionally, the C-banding pattern of the monogenic species Chrysomya albiceps is presented. The DNA contents of these and of further species Chrysomya rufifacies, Chrysomya varipes, and Chrysomya putoria were assessed on mitotic metaphases by Feulgen cytophotometry. The average 2C DNA value of the male genomes ranged from 1.04 pg in C. varipes to 2.31 pg in C. pinguis. The DNA content of metaphase X chromosomes varied from 0.013 pg (= 1.23% of the total genome) in C. varipes to 0.277 pg (12.20%) in L. sericata; that of Y chromosomes ranged from 0.003 pg (0.27%) in C. varipes to 0.104 pg (5.59%) in L. sericata. In most species, the corresponding 5 large chromosome pairs showed similar relative DNA contents. The data suggest that the interspecific DNA differences in most species are mainly due to quantitative variation of (repetitive) sequences lying outside the centromeric heterochromatin blocks of the large chromosomes. The results are also discussed with regard to phylogenetic relationships of some species.

Molecular phylogeny of the blowfly genus Chrysomya

“…1). The close relationship between Chrysomya putoria (Weidemann) and Chrysomya marginalis (Weidemann) was in agreement with Ullerich & Schottke (2006), who based their conclusions on karyotype patterns. We observed strong branch support for the species pairs: Ch.…”

“…1), with all other species for which the reproductive system is known to be amphogenic, strongly indicate that monogeny is derived rather than representative of an ancestral state in Chrysomya (Puchalla, 1994;Ullerich & Schottke, 2006). Similarly, the hypothesis of Ullerich & Schottke (2006), that the average 2C DNA content in Chrysomya spp. increased over evolutionary time (see Table 1 in Ullerich & Schottke (2006) for DNA content values), appears to be incorrect.…”

“…Chrysomya bezziana Villeneuve larvae feed on healthy warm-blooded vertebrates, and are serious medical and veterinary pests (Zumpt, 1951(Zumpt, , 1965. With about 36 species (Boyes & Shewell, 1975;Wells & Kurahashi, 1996;Ullerich & Schottke, 2006), the genus is not unusually large for the Calliphoridae. However, compared with other blowfly genera, the Chrysomya are notably diverse in morphology and habits, and some of their unique features may have contributed to the ability of several species to spectacularly succeed in invading new geographic regions.…”

“…Ullerich & Schottke (2006) Correspondence: Baneshwar Singh, Department of Biology, West Virginia University, Morgantown, WV 26505, U.S.A. Tel.…”

“…In the so-called monogenic Ch. rufifacies and Chrysomya albiceps Wiedemann, sex is determined by the mother's genotype, so that a female produces offspring of a single sex (Ullerich, 1958(Ullerich, , 1963Ullerich & Schottke, 2006). Ullerich (1976) suggested that monogeny evolved from amphogeny because monogenic species had what he believed was a derived karyotype.…”