Departamento Ciências Biológicas, Faculdade de Ciências, Universidade Estadual Paulista "Júlio de Mesquita Filho", Bauru, SP, Brazil.
Genet Mol Biol. 2011 Apr;34(2):220-4. doi: 10.1590/s1415-47572011005000009. Epub 2011 Apr 1.
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.
B 染色体是存在于大约 15%的真核生物物种中的额外染色体，通常是异染色质，表现出寄生行为，其传递率高于标准（A）染色体，并可能对携带者造成有害影响。在当前的工作中，通过涉及携带不同 B 染色体数量的亲鱼的诱导杂交，获得了携带 8 条和 9 条 B 染色体的 Prochilodus lineatus 个体。在该物种中首次记录到后代中出现的高 B 染色体数量。本研究中应用的细胞遗传学技术的使用表明，无论这些个体基因组中 B 染色体数量的增加如何，这些元素都没有表现出活性基因，并且表现出其正常的异染色质特征。
