Chromosome banding in amphibia. XXIII. Giant W sex chromosomes and extremely small genomes in Eleutherodactylus euphronides and Eleutherodactylus shrevei (Anura, Leptodactylidae).
Highly differentiated, heteromorphic ZZ female symbol /ZW male symbol sex chromosomes were found in the karyotypes of the neotropical leptodactylid frogs Eleutherodactylus euphronides and E. shrevei. The W chromosomes are the largest heterochromatic, female-specific chromosomes so far discovered in the class Amphibia. The analyses of the banding patterns with AT- and GC base-pair specific fluorochromes show that the constitutive heterochromatin in the giant W chromosomes consists of various categories of repetitive DNA sequences. The W chromosomes of both species are similar in size, morphology and banding patterns, whereas their Z chromosomes exhibit conspicuous differences. In the cell nuclei of female animals, the W chromosomes form very prominent chromatin bodies (W chromatin). DNA flow cytometric measurements demonstrate clear differences in the DNA content of male and female erythrocytes caused by the giant W chromosome, and also shows that these Eleutherodactylus genomes are among the smallest of all amphibian genomes. The importance of the heteromorphic ZW sex chromosomes for the study of Z-linked genes, the similarities and differences of the two karyotypes, and the significance of the exceptionally small genomes are discussed.
Schmid
M
M
Department of Human Genetics, Biocenter, University of Würzburg, Würzburg, Germany. m.schmid@biozentrum.uni-wuerzburg.de
Feichtinger
W
W
Steinlein
C
C
Rupprecht
A
A
Haaf
T
T
Kaiser
H
H
D000818:Animals; D001001:Anura / Q000235:genetics*; D020029:Base Pairing; D002843:Chromatin / Q000235:genetics; D002871:Chromosome Banding; D004247:DNA / Q000235:genetics; D005260:Female; D005456:Fluorescent Dyes; D016678:Genome; D019425:Grenada; D017404:In Situ Hybridization, Fluorescence; D007399:Interphase / Q000235:genetics; D007621:Karyotyping; D008297:Male; D019436:Saint Vincent and the Grenadines; D012730:Sex Chromosomes / Q000235:genetics*; D013045:Species Specificity
D002843:Chromatin; D005456:Fluorescent Dyes; D004247:DNA