title: Cytogenetic characterization of Eurysternus caribaeus (Coleoptera: Scarabaeidae): evidence of sex-autosome fusion and diploid number reduction prior to species dispersion.
abstract: Mitotic and meiotic chromosomes of several populations of Eurysternus caribaeus (Coleoptera: Scarabaeidae) were analysed through conventional staining, C-banding, base-specific fluorochromes, silver nitrate staining and fluorescent in situ hybridization (FISH). All specimens showed 2n = 8 in their karyotypes, with a neo-XY sex system (Y is a submetacentric and X a metacentric) and three pairs of submetacentric autosomes. The analysis of constitutive heterochromatin (CH) revealed small blocks located in the centromeric region of all chromosomes which do not present positive staining under the fluorochromes CMA3 and DAPI. Silver nitrate staining revealed that the nucleolar organizer region (NORs) is associated with the sex chromosomes. The FISH technique revealed that rDNA sites in the X and Y are different in size. Data from different populations indicate that the diploid number reduction (2n = 8) observed in E. caribaeus is established and presumably has preceded the dispersion of this species. Moreover, this reduction occasioned the translocation of rDNA sites to the sex chromosomes, X and Y, an uncommon pattern in Scarabaeidae that was observed for the first time by the FISH in this work.
authors.affiliation: Departamento de Biologia, Instituto de Ciencias Biológicas, UPE-Universidade de Pernambuco, 50100-130, Recife, Brazil.
authors.forename: Amanda Paulino
authors.initials: AP
authors.lastname: de Arcanjo
authors.forename: Diogo Cavalcanti
authors.initials: DC
authors.lastname: Cabral-de-Mello
authors.forename: Ana Emília
authors.initials: AE
authors.lastname: Barros e Silva
authors.forename: Rita de Cássia
authors.initials: Rde C
authors.lastname: de Moura
mesh_terms: D000818:Animals; D002871:Chromosome Banding; D001517:Coleoptera / Q000235:genetics*; D004171:Diploidy; D017344:Genes, Insect; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D009697:Nucleolus Organizer Region; D013045:Species Specificity
references.citation: Micron. 2004;35(8):717-20
references.pmid: 15288651
references.citation: Heredity (Edinb). 2008 Jun;100(6):564-73
references.pmid: 18414505
references.citation: Hereditas. 2004;140(3):161-70
references.pmid: 15198705
references.citation: Micron. 2008 Dec;39(8):1243-50
references.pmid: 18495484
references.citation: Micron. 2007;38(6):590-8
references.pmid: 17113778
references.citation: Genet Res. 1994 Dec;64(3):183-97
references.pmid: 7698642
references.citation: Hereditas. 2001;134(2):121-4
references.pmid: 11732847
references.citation: Chromosome Res. 2006;14(8):909-18
references.pmid: 17195052
references.citation: Folia Biol (Krakow). 2004;52(3-4):151-8
references.pmid: 19058553
references.citation: Cytogenet Genome Res. 2007;119(3-4):248-54
references.pmid: 18253038
references.citation: Neotrop Entomol. 2007 Jul-Aug;36(4):503-9
references.pmid: 17934611
references.citation: Hereditas. 2003;138(3):200-6
references.pmid: 14641484
references.citation: Chromosoma. 1976 Nov 29;58(4):307-24
references.pmid: 137107
references.citation: Micron. 2007;38(3):323-5
references.pmid: 16919467
references.citation: Genetica. 2006 Sep-Nov;128(1-3):333-46
references.pmid: 17028962
references.citation: Chromosome Res. 1999;7(7):503-8
references.pmid: 10598565
references.citation: Micron. 2006;37(1):47-51
references.pmid: 16140020
references.citation: Chromosome Res. 2006;14(5):549-57
references.pmid: 16823617
references.citation: Hereditas. 2004;140(1):49-60
references.pmid: 15032947
references.citation: Hereditas. 2006 Dec;143(2006):123-9
references.pmid: 17362345
references.citation: Chromosoma. 1996 Oct;105(4):231-6
references.pmid: 8854882
references.citation: Trends Genet. 2002 Nov;18(11):587-9
references.pmid: 12414190
references.citation: J Hered. 2000 May-Jun;91(3):260-4
references.pmid: 10833056
references.citation: Exp Cell Res. 1972 Nov;75(1):304-6
references.pmid: 4117921