Genetics and Molecular Biology
Print version ISSN 1415-4757
VOLTOLIN, Tatiana Aparecida et al. Intraspecific crosses resulting in the first occurrence of eight and nine B chromosomes in Prochilodus lineatus (Characiformes, Prochilodontidae). Genet. Mol. Biol. [online]. 2011, vol.34, n.2, pp. 220-224. Epub Apr 01, 2011. ISSN 1415-4757. http://dx.doi.org/10.1590/S1415-47572011005000009.
B chromosomes are supernumerary elements present in about 15% of eukaryotic species and are most frequently heterochromatic, behave parasitically, show a transmission rate higher than standard (A) chromosomes, and can provoke harmful effects on carriers. In the current work, Prochilodus lineatus individuals carrying eight and nine B chromosomes were obtained by induced crossing performed involving breeders with different B chromosome numbers in their cells. The high B chromosome numbers found in the offspring were recorded for the first time in this species. The use of cytogenetic techniques applied in the present study revealed that regardless of the increase in number of B chromosomes in the genome of these individuals, those elements did not presented active genes, and showed their normal heterochromatic characteristic.
Keywords : supernumerary chromosome; heterochromatic chromosome; cross-fertilization.