Transmission Behavior of B Chromosomes in Prochilodus lineatus (Characiformes, Prochilodontidae)

摘要

The population of Prochilodus lineatus found in the MogiGuacu River is karyotypically polymorphic, carrying acrocentric, metacentric, and submetacentric B chromosomes. The analysis of each B chromosome frequency in this species revealed a variation in the distribution pattern, with the metacentric type having the highest frequency (73.30%), followed by submetacentric (25.22%) and acrocentric B chromosomes (1.48%). The transmission pattern of the supernumerary chromosomes was identified by controlled crosses, and it was shown that the acro- and submetacentric B chromosomes have a transmission pattern below the Mendelian rate (k(B) = 0.333 and k(B) = 0.385, respectively), but the metacentric variant has a cumulative transmission pattern (k(B) = 0.587). These results indicate that the acro-and submetacentric B chromosomes are undergoing an extinction process, while the metacentric B chromosomes appear to be accumulating in frequency with each generation. (C) 2016 S. Karger AG, Basel