tailieunhanh - Báo cáo sinh học: "Variation of sperm length and in drosophilid species"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: Variation of sperm length and in drosophilid species | Genet. Sei. Evol. 1989 21 283-293 Elsevier IN R A 283 Original article Variation of sperm length and heteromorphism in drosophilid species D. Joly . Cariou D. Lachaise and . David Centre National de la Recherche Scientiflque laboratoire de biologie et génétique évolutives 91198 Gif-sur-Yvette Cedex France received 8 December 1988 accepted 17 April 1989 Summary - Sperm length was measured in 27 drosophilid species and a general survey of size variation is presented for 75 species for which information is available. Mean length varies from 0 113 mm in the D. obscura group to almost 20 mm in the recently investigated D. littoralis in the latter case sperm length is nearly 6 times the male body length. The huge interspecific variability may be estimated by considering the coefficient of variation . between species belonging to the same taxon. In the genus Drosophila the . amounts to 130 64 species . The average . decreases in lower taxa being for example 96 in subgenera and 61 in species groups. More closely related species are thus less divergent but in any case sperm length must be considered as a fast evolving trait increasing or decreasing. Individual measurements of sperm length within a species generally providẹ a unimonal relatively gaussian distribution monomorphism . By contrast 13 investigated species of the D. obscura group exhibited bimodal distributions. This heteromorphism may be considered as a stable evolutionary strategy in the D. obscura group. Drosophila - sperm length - sperm heteromorphism - sperm evolution Resume Variation de la longueur des spermatozo ides et hétéromorphisme chez les drosophilides. La longueur des spermatozoides mesures chez 27 espèces de Drosophilides est étudiée au niveau de I ensemble de la famille 75 espèces . Les moyennes de longueur variant de 0 113 mm chez les espèces du groupes obscura jusqu a 20 mm chez une esp ece nouvellement étudiée D. littoralis chez cette demiere la longueur du spermatozoideat-teint