title: Chromosome evolution in fish: BrdU replication patterns demonstrate chromosome homeologies in two species of the genus Astyanax.
abstract: A comparison of R-banding patterns obtained by 5-bromodeoxyuridine incorporation was made between the chromosomes of two fish species of the genus Astyanax (Characiformes: Tetragonopterinae), A. altiparanae with 2n = 50 chromosomes, and A. schubarti with 2n = 36 chromosomes. The two species present the highest and the lowest chromosome numbers found in this fish genus, respectively, for which the modal chromosome number is 50. R-band homeology was detected, involving eleven chromosomes of A. schubarti and seventeen chromosomes of A. altiparanae, indicating a close chromosomal relationship between the two species, in spite of their great difference in chromosome number. A chromosome fusion in the past history of the group was hypothesized as a possible cause of the discrepant chromosome numbers of the two species.
authors.affiliation: Departamento de Biologia, Instituto de Biociências, Universidade de São Paulo, SP, Brazil.
authors.forename: M F Z
authors.initials: MF
authors.lastname: Daniel-Silva
authors.forename: L F
authors.initials: LF
authors.lastname: Almeida-Toledo
mesh_terms: D000818:Animals; D001938:Brazil; D001973:Bromodeoxyuridine / Q000737:chemistry*; D002871:Chromosome Banding / Q000379:methods; D002875:Chromosomes / Q000737:chemistry* / Q000235:genetics*; D020732:Cytogenetic Analysis / Q000379:methods; D019143:Evolution, Molecular; D005260:Female; D005399:Fishes / Q000235:genetics*; D005828:Genetics, Population / Q000379:methods; D008297:Male; D008938:Mitosis / Q000235:genetics; D045483:Rivers; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity
chemical_list: D001973:Bromodeoxyuridine