(041208 revised, 041208 created)
Abstract
Heliconius melpomene is a mimetic butterfly that exhibits great geographic variation in color pattern. We here present a genetic linkage map based on analysis of genetic markers in 73 individuals from a single F2 family, offspring of a cross between H. m. cythera from western Ecuador and H. m. melpomene from French Guiana. A novel "three-step method" is described for the analysis of dominant markers in an F2 cross, using outbred parental strains and taking advantage of the lack of crossing over in female Lepidoptera. This method is likely to prove useful for future mapping studies in outbred species with crossing over restricted to one sex, such as the Lepidoptera and Drosophila. The resulting linkage map has 21 linkage groups corresponding to the 21 chromosomes of H. melpomene, and includes 219 AFLP markers, 23 microsatellites, 19 single copy nuclear genes and the color pattern switch genes Yb and Sb. The marker density is high, averaging more than 1 per 7 cM. The total map length is 1616 cM and the average chromosome length is 77cM. The genome size of H. melpomene was estimated to be 292 Mb, giving a relationship of physical to map distance of 180 kb/cM. This map forms the basis for future comparative linkage analysis of color pattern evolution in Heliconius.
Heliconius melpomene : English name: the Cattle Heart. A "bowtie" butterfly having beautiful jet black & bright red colors. Japanese name:メルポメネドクチョウ. 亜熱帯性ドクチョウ Heliconius erato と H. melpomene は、南アメリカ北部の広範囲に生息する。2種はミュラー型擬態をしており、同じ模様を持つものが捕食者へ学習されやすく有利なため、ひとつの翅パターンに収斂されると予想されるが，実際には多彩な翅パターンが維持されている。地理分布はモザイク状で、同じ地域では2種の翅パターンが酷似する。
left: Heliconius melpomene, right : Heliconius cydno, center: their F1 hybrid.