Comparative Genomic Hybridization (CGH) of sex chromosomes in Anastrepha fraterculus from Argentina

GIARDINI, M.CECILIA; MILLA, F; CLADERA, J.; LANZAVECCHIA, S; NIEVES, MARIELA

Congreso; International Congress of Genetics; 2018

Anastrepha fraterculus Wied. (Diptera: Tephritidae) is an important fruit pest in South America. Currently seven cryptic species or morphotypes have been described. To find a trait to distinguish them poses a challenge to pest control practice. The existence of variation in the morphology of sex chromosomes between and within A. fraterculus morphs has been demonstrated using classical bandings methods. In order to improve this sex chromosomes characterization we have here adapted for these taxa the comparative genomic hybridization (CGH) technique. In Argentina we are studying the morphotype A. fraterculus sp. 1 or Brazilian 1 morphotype which prevails here. This fly has a diploid set of 2n= 12 chromosomes including a pair of sex chromosomes, XX in females and XY in males. Genomic DNA was separately extracted from adult females and males using octanol/chloroform protocol. The labeling of genomic probes was done by nick translation procedure with rhodamine and fluorescein. CGH analysis of male preparations evidenced that the Y chromosome shows female-DNA in the centromeric region and presents only-male DNA sequences on the rest of its length. The X chromosome, on the contrary, exhibits only-female DNA sequences in its entire length. The same was observed in both X chromosomes from females. The results reported here represent an important step towards the differentiation of A. fraterculus sex chromosomes. This information could be potentially useful to characterize other members of this complex by mean of Molecular Cytogenetics