PT - JOURNAL ARTICLE AU - Tomkiel, John E. AU - Wakimoto, Barbara T. AU - Briscoe, Albert TI - The <em>teflon</em> Gene Is Required for Maintenance of Autosomal Homolog Pairing at Meiosis I in Male <em>Drosophila melanogaster</em> DP - 2001 Jan 01 TA - Genetics PG - 273--281 VI - 157 IP - 1 4099 - http://www.genetics.org/content/157/1/273.short 4100 - http://www.genetics.org/content/157/1/273.full SO - Genetics2001 Jan 01; 157 AB - In recombination-proficient organisms, chiasmata appear to mediate associations between homologs at metaphase of meiosis I. It is less clear how homolog associations are maintained in organisms that lack recombination, such as male Drosophila. In lieu of chiasmata and synaptonemal complexes, there must be molecules that balance poleward forces exerted across homologous centromeres. Here we describe the genetic and cytological characterization of four EMS-induced mutations in teflon (tef), a gene involved in this process in Drosophila melanogaster. All four alleles are male specific and cause meiosis I-specific nondisjunction of the autosomes. They do not measurably perturb sex chromosome segregation, suggesting that there are differences in the genetic control of autosome and sex chromosome segregation in males. Meiotic transmission of univalent chromosomes is unaffected in tef mutants, implicating the tef product in a pairing-dependent process. The segregation of translocations between sex chromosomes and autosomes is altered in tef mutants in a manner that supports this hypothesis. Consistent with these genetic observations, cytological examination of meiotic chromosomes suggests a role of tef in regulating or mediating pairing of autosomal bivalents at meiosis I. We discuss implications of this finding in regard to the evolution of heteromorphic sex chromosomes and the mechanisms that ensure chromosome disjunction in the absence of recombination.