title: Transmission analysis of mitotically unstable B chromosomes in Locusta migratoria.
abstract: Seventeen controlled crosses in which the mitotically unstable B chromosome of Locusta migratoria was carried by one parent only have provided evidence that B chromosomes are significantly eliminated during sexual transmission in males, at a mean rate that almost counteracts the premeiotic accumulation derived from mitotic instability during germ line development. On the other hand, B chromosomes are significantly accumulated in females, presumably by their preferential migration to the secondary oocyte during the first meiotic division. These results substantially change the current knowledge about this B chromosome system, because the main B accumulation occurs in females and not in males, as was hitherto thought. Furthermore, this case shows that the maintenance of a single B system in natural populations may be the result of many different forces and mechanisms acting for and against B chromosomes.
authors.forename: M C
authors.initials: MC
authors.lastname: Pardo
authors.forename: M D
authors.initials: MD
authors.lastname: López-León
authors.forename: J
authors.initials: J
authors.lastname: Cabrero
authors.forename: J P
authors.initials: JP
authors.lastname: Camacho