Utsunomia Ricardo, Melo Silvana, Scacchetti Priscilla Cardim, Oliveira Claudio, Machado Milla de Andrade, Pieczarka Julio Cesar, Nagamachi Cleusa Yoshiko, Foresti Fausto
1 Laboratório de Biologia e Genética de Peixes, Department of Morphology, Institute of Biosciences of Botucatu, São Paulo State University , Botucatu, SP, Brazil .
2 Laboratório de Citogenética, Centro de Estudos Avançados da Biodiversidade, Instituto de Ciências Biológicas, Universidade Federal do Pará , Belém, PA, Brazil .
Zebrafish. 2018 Aug;15(4):398-403. doi: 10.1089/zeb.2018.1570. Epub 2018 Jun 21.
Microsatellites show great abundance in eukaryotic genomes, although distinct chromosomal distribution patterns might be observed, from small dispersed signals to strong clustered motifs. In Neotropical fishes, the chromosome mapping of distinct microsatellites was employed several times to uncover the origin and evolution of sex and supernumerary chromosomes, whereas a detailed comparative analysis considering different motifs at the chromosomal level is scarce. Here, we report the chromosomal location of several simple sequence repeats (SSRs) in distinct electric knife fishes showing variable diploid chromosome numbers to unveil the structural organization of several microsatellite motifs in distinct Gymnotus species. Our results showed that some SSRs are scattered throughout the genomes, whereas others are particularly clustered displaying intense genomic compartmentalization. Interestingly, the motifs CA, GA, and GAG exhibited a band-like pattern of hybridization, useful for the identification of homologous chromosomes. Finally, the colocalization of SSRs with multigene families is probably related to the association of microsatellites with gene spacers in this case.
微卫星在真核生物基因组中大量存在，尽管可能观察到不同的染色体分布模式，从小的分散信号到强烈的聚集基序。在新热带鱼类中，不同微卫星的染色体定位多次被用于揭示性染色体和超数染色体的起源与进化，然而在染色体水平上考虑不同基序的详细比较分析却很缺乏。在这里，我们报告了几种电刀鱼中几个简单序列重复（SSR）的染色体定位，这些电刀鱼显示出不同的二倍体染色体数，以揭示不同裸背电鳗属物种中几种微卫星基序的结构组织。我们的结果表明，一些SSR分散在整个基因组中，而其他的则特别聚集，显示出强烈的基因组分区。有趣的是，基序CA、GA和GAG表现出带状杂交模式，有助于同源染色体的识别。最后，在这种情况下，SSR与多基因家族的共定位可能与微卫星与基因间隔区的关联有关。
