Autor(es): Degrandi, Tiago Marafiga ; Gunski, Ricardo Jos? ; Garnero, Anal?a del Valle ; Oliveira, Edivaldo Herculano Correa de ; Krestschmer, Rafael ; Souza, Marcelo Santos de ; Barcellos, Suziane Alves ; Hass, Iris
Data: 2020
Origem: Oasisbr
Assunto(s): Aves / anatomia & histologia; Aves / gen?tica; An?lise Citogen?tica; Cari?tipo
Coordena??o de Aperfei?oamento de Pessoal de Nivel Superior
Universidade Federal do Paran?. Departamento de Gen?tica. Curitiba, PR, Brazil.
Universidade Federal do Pampa. S?o Gabriel, RS, Brazil.
Universidade Federal do Pampa. S?o Gabriel, RS, Brazil.
Universidade Federal do Par?. Bel?m, PA, Brazil / Minist?rio da Sa?de. Secretaria de Vigil?ncia em Sa?de. Instituto Evandro Chagas. Laborat?rio Cultura de Tecidos e Citogen?tica. Ananindeua, PA, Brasil.
Universidade Federal do Rio Grande do Sul. Instituto de Bioci?ncias. Porto Alegre, RS, Brazil.
Universidade Federal do Pampa. S?o Gabriel, RS, Brazil.
Universidade Federal do Pampa. S?o Gabriel, RS, Brazil.
Universidade Federal do Paran?. Departamento de Gen?tica. Curitiba, PR, Brazil.
The distribution of 45S rDNA cluster in avian karyotypes varies in different aspects, such as position, number of bearer chromosomes, and bearers being macro- or microchromosomes. The present study investigated the patterns of variation in the 45S rDNA-bearer chromosomes of birds in order to understand the evolutionary dynamics of the cluster configuration and its contribution to the evolution of bird karyotypes. A total of 73 bird species were analyzed, including both published data and species for which rDNA-FISH was conducted for the first time. In most birds, the 45S rDNA clusters were located in a single pair of microchromosomes. Hence, the location of 45S rDNA in macrochromosomes, observed only in Neognathae species, seems to be a derived state, probably the result of chromosomal fusion between microchromosomes and distinct macrochromosomes. Additionally, the 45S rDNA was observed in multiple microchromosomes in different branches of the bird phylogeny, suggesting recurrence of dispersion processeses, such as duplications and translocations. Overall, this study indicated that the redistribution of the 45S rDNA sites in bird chromosomes followed different evolutionary trajectories with respect to each lineage of the class Aves.
