Chromosome size differences may affect meiosis and genome size.
Genetic crosses in many organisms have shown that alleles of unlinked genes generally assort independently of one another during gamete formation. However, variation in chromosome size may affect the process of meiosis and lead to nonindependent assortment of chromosomes. We therefore examined chromosomes with insertions and found that they preferentially segregated away from the X chromosome during meiosis in Caenorhabditis elegans males. Conversely, chromosomes with deletions preferentially segregated with the X chromosome. The degree of segregation bias was significantly associated with the length of the insertion or deletion. Simulations revealed that this segregation bias leads to genome size reduction in hermaphroditic species, a pattern consistent with differences in genome sizes in the genus Caenorhabditis. These results suggest that insertions and deletions may affect chromosome segregation patterns.
Wang
John
J
Department of Ecology and Evolution, University of Lausanne, CH-1015 Lausanne, Switzerland. John.Wang@unil.ch
Chen
Pei-Jiun
PJ
Wang
George J
GJ
Keller
Laurent
L
D000818:Animals; D017173:Caenorhabditis elegans / Q000235:genetics* / Q000502:physiology; D002872:Chromosome Deletion; D020090:Chromosome Segregation; D002875:Chromosomes / Q000235:genetics*; D012734:Disorders of Sex Development; D005260:Female; D016678:Genome; D054643:INDEL Mutation; D008297:Male; D008540:Meiosis; D016254:Mutagenesis, Insertional; D019076:Transgenes; D014960:X Chromosome / Q000235:genetics