title: Genomic Organization Under Different Environmental Conditions: Hoplosternum Littorale as a Model.
abstract: The Amazon has abundant rivers, streams, and floodplains in both polluted and nonpolluted environments, which show great adaptability. Thus, the goal of this study was to map repetitive DNA sequences in both mitotic chromosomes and erythrocyte micronuclei of tamoatás from polluted and nonpolluted environments and to assess the possible genotoxic effects of these environments. Individuals were collected in Manaus, Amazonas (AM), and submitted to classical and molecular cytogenetic techniques, as well as to a blood micronucleus test. Diploid number equal to 60 chromosomes are present in all individuals, with 18S ribosomal DNA sites present in one chromosome pair and no interstitial telomeric sites on chromosomes. The micronucleus test showed no significant differences in pairwise comparisons between environments or collection sites, but the Rex3 retroelement was dispersed on the chromosomes of individuals from unpolluted environments and compartmentalized in individuals from polluted environments. Divergent numbers of 5S rDNA sites are present in individuals from unpolluted and polluted environments. The mapping of repetitive sequences revealed that micronuclei have different compositions both intra- and interindividually that suggests different regions are lost in the formation of micronuclei, and no single fragile region undergoes breaks, although repetitive DNA elements are involved in this process.
authors.affiliation: 1 Laboratório de Citogenômica Animal, Instituto de Ciências Biológicas , Universidade Federal do Amazonas, Manaus, Brazil .
authors.forename: Francijara Araújo da
authors.initials: FA
authors.lastname: Silva
authors.affiliation: 1 Laboratório de Citogenômica Animal, Instituto de Ciências Biológicas , Universidade Federal do Amazonas, Manaus, Brazil .
authors.forename: Carlos Henrique
authors.initials: CH
authors.lastname: Schneider
authors.affiliation: 2 Laboratório de Genética Animal, Instituto Nacional de Pesquisas da Amazônia , Manaus, Brazil .
authors.forename: Eliana
authors.initials: E
authors.lastname: Feldberg
authors.affiliation: 3 Laboratório de Zoologia, Instituto de Ciências Biológicas, Universidade Federal do Amazonas , Manaus, Brazil .
authors.forename: Fabricio Beggiato
authors.initials: FB
authors.lastname: Baccaro
authors.affiliation: 1 Laboratório de Citogenômica Animal, Instituto de Ciências Biológicas , Universidade Federal do Amazonas, Manaus, Brazil .
authors.forename: Natália Dayane Moura
authors.initials: ND
authors.lastname: Carvalho
authors.affiliation: 1 Laboratório de Citogenômica Animal, Instituto de Ciências Biológicas , Universidade Federal do Amazonas, Manaus, Brazil .
authors.forename: Maria Claudia
authors.initials: MC
authors.lastname: Gross
mesh_terms: D000818:Animals; D002397:Catfishes / Q000235:genetics*; D002874:Chromosome Mapping; D004275:DNA, Ribosomal / Q000235:genetics; D017753:Ecosystem; D044127:Epigenesis, Genetic; D023281:Genomics; D008938:Mitosis; D012337:RNA, Ribosomal, 18S / Q000235:genetics; D012341:RNA, Ribosomal, 5S; D045483:Rivers
chemical_list: D004275:DNA, Ribosomal; D012337:RNA, Ribosomal, 18S; D012341:RNA, Ribosomal, 5S