title: The non-random occurrence of Robertsonian fusion in the house mouse.
abstract: Chromosomal rearrangements such as Robertsonian (Rb) fusions constitute a major phenomenon in the evolution of genome organization in a wide range of organisms. Although proximate mechanisms for the formation of Rb fusion are now well identified, the evolutionary forces that drive chromosomal evolution remain poorly understood. In the house mouse, numerous chromosomal races occur in nature, each defined by a unique combination of Rb fusions. Among the 106 different Rb fusions that were reported from natural populations, the low involvement of chromosome 19 in Rb fusions is striking, prompting the question of the randomness of chromosomal involvement in Rb fusions. We uncover a significant quadratic relationship between chromosome size and probability of fusing, which has never previously been in this species. It appears that fusions involving chromosome 19 are not particularly infrequent, given the expected low fusion probability associated with the chromosome's size. The results are discussed, assessing selective processes or constraints that may operate on chromosome size.
authors.affiliation: Institut des Sciences de l'Evolution, UMR CNRS, CC 064, Université de Montpellier II, 34095 Montpellier cedex 5, France. gazave@isem.univ-montp2.fr
authors.forename: Elodie
authors.initials: E
authors.lastname: Gazave
authors.forename: Josette
authors.initials: J
authors.lastname: Catalan
authors.forename: Maria da Graça
authors.initials: Mda G
authors.lastname: Ramalhinho
authors.forename: Maria da Luz
authors.initials: Mda L
authors.lastname: Mathias
authors.forename: Ana Claudia
authors.initials: AC
authors.lastname: Nunes
authors.forename: David
authors.initials: D
authors.lastname: Dumas
authors.forename: Janice
authors.initials: J
authors.lastname: Britton-Davidian
authors.forename: Jean-Christophe
authors.initials: JC
authors.lastname: Auffray
mesh_terms: D000818:Animals; D005075:Biological Evolution; D002875:Chromosomes; D051379:Mice / Q000235:genetics*