title: Genomic in situ hybridization reveals both auto- and allopolyploid origins of different North and Central American hexaploid potato (Solanum sect. Petota) species.
abstract: Wild potato ( Solanum  L. sect.  Petota  Dumort.) species contain diploids (2n = 2x = 24) to hexaploids (2n = 6x = 72). J.G. Hawkes classified all hexaploid Mexican species in series  Demissa  Bukasov and, according to a classic five-genome hypothesis of M. Matsubayashi in 1991, all members of series Demissa are allopolyploids. We investigated the genome composition of members of Hawkes's series Demissa with genomic in situ hybridization (GISH), using labeled DNA of their putative progenitors having diploid AA, BB, or PP genome species or with DNA of tetraploid species having AABB or AAA(a)A(a) genomes. GISH analyses support  S. hougasii  Correll as an allopolyploid with one AA component genome and another BB component genome. Our results also indicate that the third genome of S. hougasii is more closely related to P or a P genome-related species.  Solanum demissum  Lindl., in contrast, has all three chromosome sets related to the basic A genome, similar to the GISH results of polyploid species of series  Acaulia  Juz. Our results support a more recent taxonomic division of the Mexican hexaploid species into two groups: the allopolyploid Iopetala group containing S. hougasii, and an autopolyploid Acaulia group containing S. demissum with South American species  S. acaule  Bitter and  S. albicans  (Ochoa) Ochoa.
authors.affiliation: Department of Biotechnology, N.I. Vavilov Institute of Plant Industry, Bolshaya Morskaya Street, 42-44, St. Petersburg, 190000, Russia.
authors.forename: Galina
authors.initials: G
authors.lastname: Pendinen
authors.forename: David M
authors.initials: DM
authors.lastname: Spooner
authors.forename: Jiming
authors.initials: J
authors.lastname: Jiang
authors.forename: Tatjana
authors.initials: T
authors.lastname: Gavrilenko
mesh_terms: D002489:Central America; D032461:Chromosomes, Plant / Q000235:genetics*; D018744:DNA, Plant / Q000235:genetics*; D018745:Genome, Plant; D023281:Genomics; D017403:In Situ Hybridization; D058889:Molecular Typing; D009656:North America; D010802:Phylogeny; D058974:Phylogeography; D011003:Ploidies; D032322:Solanum / Q000145:classification / Q000235:genetics*; D013045:Species Specificity
chemical_list: D018744:DNA, Plant