J Syst Evol ›› 2014, Vol. 52 ›› Issue (3): 250-259.DOI: 10.1111/jse.12091

• Research Articles • Previous Articles     Next Articles

Origin of Ostryopsis intermedia (Betulaceae) in the southeast Qinghai–Tibet Plateau through hybrid speciation

1Zhi‐Qiang LU§ 2Bin TIAN§ 1Bing‐Bing LIU 1Chen YANG 1Jian‐Quan LIU*   

  1. 1(State Key Laboratory of Grassland Agro-Ecosystem, School of Life Sciences, Lanzhou University, Lanzhou 730000, China)
    2(Key Laboratory of Biodiversity Conservation in Southwest China, State Forestry Administration, Southwest Forestry University, Kunming 650224, China)
  • Received:2013-12-24 Published:2014-05-09

Abstract: It remains unknown how Ostryopsis intermedia B. Tian & J. Q. Liu (Betulaceae) originated in the SE Qinghai–Tibet Plateau (QTP). We examined sequence variations of two maternally inherited chloroplast (cp) DNA fragments and amplified fragment length polymorphisms (AFLP) of 32 populations for this species and two congeners, O. davidiana Decne. and O. nobilis Balf. f. W. W. Sm., distributed in northern China and the SE QTP. Each of the two distinct cpDNA haplotype groups was fixed by O. davidiana or O. intermedia, respectively, whereas both were found in O. nobilis. All analyses of AFLP suggested that O. intermedia is more closely related to O. davidiana than to O. nobilis and Bayesian clustering analysis (K = 2) further suggested that the genomic composition of O. intermedia showed a slightly mosaic origin from the other two species, although mostly from O. davidiana. Analyses of AFLP indicated the highest nuclear genetic diversity for O. davidiana and lowest forO. intermedia. The origin of O. intermedia through hybrid speciation due to southward migration of O. davidiana and the following hybridization with O. nobilis may provide the most reasonable explanation for the inconsistency between phylogenetic relationships of three species and degrees of genetic diversity from cpDNA sequences or AFLP datasets. Ostryopsis intermedia may represent one more diploid hybrid species found in the QTP, although further strong tests are needed based on additional data.

Key words: diploid hybrid speciation, Ostryopsis intermedia, QTP.