Ribeiro L B, Matoso D A, Almeida M C, Vicari M R, Moraes-Neto A, Svidnicki M C C M, Artoni R F
Programa de Pós-Graduação em Genética, Conservação e Biologia Evolutiva, Instituto Nacional de Pesquisas da Amazônia, Manaus, AM, Brasil.
Genet Mol Res. 2008;7(3):718-24. doi: 10.4238/vol7-3gmr456.
Cytogenetic analyses were carried out in a populational sample of Iheringichthys labrosus from the Guaraúna River (Upper Tibagi River; Paraná State, Brazil) in order to provide a karyotypic comparison with another previously studied population from the Lower Tibagi River, characterized by the presence of 32m + 8sm + 6st + 10a (2n = 56, FN = 102) and occurrence of supernumerary chromosomes (80% of individuals). The 17 specimens of I. labrosus (6 females, 10 males and 1 of unknown sex) from the Upper Tibagi River showed 2n = 56 chromosomes, a karyotype formula of 14m + 32sm + 4st + 6a (FN = 106), without evidence of sex chromosome heteromorphism or supernumerary chromosomes. The heterochromatin was detected at telomeric and centromeric positions in several chromosomal pairs. The Ag-nucleolar organizer regions were heteromorphic and located at terminal position on short arms of the 16th chromosomal pair, suggesting a positive association with heterochromatic regions. The inter-populational karyotypic differentiation reported indicates distinct evolutionary pathways within I. labrosus in the Tibagi River basin.
对来自瓜劳纳河（上提巴吉河；巴西巴拉那州）的拉氏伊氏脂鲤种群样本进行了细胞遗传学分析，以便与先前研究的来自下提巴吉河的另一个种群进行核型比较，该种群的特征是有32条中着丝粒染色体 + 8条亚中着丝粒染色体 + 6条近端着丝粒染色体 + 10条端着丝粒染色体（2n = 56，臂数 = 102），并且存在超数染色体（80%的个体）。来自上提巴吉河的17个拉氏伊氏脂鲤标本（6只雌性、10只雄性和1只性别未知）显示有2n = 56条染色体，核型公式为14条中着丝粒染色体 + 32条亚中着丝粒染色体 + 4条近端着丝粒染色体 + 6条端着丝粒染色体（臂数 = 106），没有性染色体异形或超数染色体的证据。在几个染色体对的端粒和着丝粒位置检测到了异染色质。银染核仁组织区呈异形，位于第16对染色体短臂的末端位置，表明与异染色质区域呈正相关。所报道的种群间核型分化表明提巴吉河流域的拉氏伊氏脂鲤存在不同的进化途径。
