Fax +41 61 306 12 34 E-Mail karger@karger.ch www.karger.com Cytogenet Genome Res DOI: 10.1159/000314285 Silene latifolia: The Classical Model to Study Heteromorphic Sex Chromosomes E. Kejnovsky B. Vyskot Institute of Biophysics, Academy of Sciences, Brno, Czech Republic trolled, although some are environmentally and/or hor- monally influenced. Genetically controlled gender in di- oecious plant species is widespread, but there are only a few species that possess heteromorphic sex chromo- somes, including species from genera Silene, Rumex, Hu- mulus, Cannabis, and Coccinia [for review, see Vyskot and Hobza, 2004]. Several of these species possess X and Y chromosomes, usually XX in homogametic females and XY in heterogametic males. In a majority of these species, the Y chromosome is the largest in the genome accumulating a large amount of satellite and transposable element DNA sequences. Both homomorphic sex chro- mosomes (e.g. papaya, asparagus) and heteromorphic plant sex chromosomes are relatively young. According to recent molecular phylogenetic analyses, they began evolving about 5–20 million years ago [Filatov, 2005a; Navajas-Perez et al., 2005; Nicolas et al., 2005] while, e.g., mammalian sex chromosomes have been evolving for around 150 million years [Graves, 2002]. Provided that the molecular mechanisms of evolution are common among plant and animal lineages, we can shed light on the early steps of evolution of mammalian sex chromo- somes by studying plant models. Silene latifolia (formerly Melandrium album) or white campion belongs to the Caryophyllaceae family. S. latifo- lia is a perennial herb, a weed now common nearly all Key Words Genome  Repetitive sequences  Sex chromosomes  Silene latifolia Abstract This review summarizes older as well as recent data about the model dioecious plant Silene latifolia. This plant has been the subject of more than one hundred years of research ef- forts and its most conspicuous property is huge and well dif- ferentiated heteromorphic sex chromosomes, XX in females and XY in males. Due to this property the S. latifolia sex chro- mosomes have been often used for cytogenetic studies as well as for flow sorting and laser microdissection. Nowadays S. latifolia is the focus of genomic studies, molecular map- ping, phylogenetic and population genetics analyses. Copyright © 2010 S. Karger AG, Basel Historical Background There are about 300,000 species of flowering (angio- sperm) plants and only about 10,000 of these are dioe- cious, that is, forming individuals of different sexes [Yam- polsky and Yampolsky, 1922]. Sex determination in the majority of dioecious plant species is genetically con- Published online: June 10, 2010 Boris Vyskot Laboratory of Plant Developmental Genetics Institute of Biophysics, Kralovopolska 135 CZ–61265 Brno (Czech Republic) Tel./Fax +420 5 4124 0500, E-Mail vyskot  @  ibp.cz © 2010 S. Karger AG, Basel 1424–8581/10/0000–0000$26.00/0 Accessible online at: www.karger.com/cgr