Open AccessUnusual sex chromosome inheritance in six species of small ermine moths ( Yponomeuta , Yponomeutidae, Lepidoptera)
Author(s) -
NILSSON NILSOTTO,
‘LÖFSTEDT CHRJSTER,
DÄVRING LARS
Publication year - 1988
Publication title -
hereditas
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 50
eISSN - 1601-5223
pISSN - 0018-0661
DOI - 10.1111/j.1601-5223.1988.tb00311.x
Subject(s) - heterogametic sex , biology , autosome , bivalent (engine) , genetics , chromosome , meiosis , x chromosome , homologous chromosome , ploidy , lepidoptera genitalia , sex linkage , w chromosome , zoology , karyotype , botany , chemistry , organic chemistry , gene , metal
First meiotic division in females and males of Yponomeuta evonyrnellus (L.), Y. cagnagellus (Hiibner). Y. rnalinellus Zeller, Y. padellus (L), Y. rorellus (Hiibner) and Y. gigas Rebel was studied in the light microscope. In the heterogametic females the sex chromosomes were found to be associated in a sex chromosome trivalent. The sex chromosome trivalent, written AA W Z, consisted of a W‐chromosome translocated to an autosome to form an A w ‐chromosome, which was paired with the homologous auto‐some and the 2‐chromosome. In the homogametic males the two Z‐chromosomes were paired in a usual bivalent. The sex chromosome inheritance can be balanced in this way. The haploid chromosome number was n = 29 A + AA W Z in females and n = 30 A + ZZ in males, for all species examined. It is of interest to notice that the chromosome number of Y. rorellus earlier has been differently determined to be n = 29 for males. Especially in females the bivalents were observed to be nonhomologously associated at the telomeres during meiotic prophase.