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ARS Home » Pacific West Area » Corvallis, Oregon » National Clonal Germplasm Repository » Research » Publications at this Location » Publication #311093

Research Project: Management of Temperate-Adapted Fruit, Nut, and Specialty Crop Genetic Resources and Associated Information

Location: National Clonal Germplasm Repository

Title: Phylogeny and evolutionary histories of Pyrus L. revealed by phylogenetic trees and networks based on data from multiple DNA sequences

Author
item ZHENG, XIAOYAN - Zhejiang University
item CAI, DANYING - Zhejiang University
item POTTER, DANIEL - University Of California
item Postman, Joseph
item LIU, JING - Zhejiang University
item TENG, YUANWEN - Zhejiang University

Submitted to: Molecular Phylogenetics and Evolution
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/1/2014
Publication Date: 9/1/2014
Citation: Zheng, X., Cai, D., Potter, D., Postman, J.D., Liu, J., Teng, Y. 2014. Phylogeny and evolutionary histories of Pyrus L. revealed by phylogenetic trees and networks based on data from multiple DNA sequences. Molecular Phylogenetics and Evolution. 80:54-65.

Interpretive Summary: It has been difficult to determine the ancestry relationship between different pear species, especially those from different parts of the world. In this study, we collected samples from 110 different pear trees representing 25 Pyrus species. The relationships between each sample was determined based on different DNA sequences. Computer analysis of the sequences suggested that pear species from Southwestern China may be the ancient ancestors of many different pear species, although there were not enough European pear samples included to fully understand the evolutionary histories of some species groups.

Technical Abstract: Reconstructing the phylogeny of Pyrus has been difficult due to the wide distribution of the genus and lack of informative data. In this study, we collected 110 accessions representing 25 Pyrus species and constructed both phylogenetic trees and phylogenetic networks based on multiple DNA sequence datasets. Phylogenetic trees based on both cpDNA and nuclear LFY2int2-N (LN) data resulted in poor resolution, especially, only five primary species were monophyletic in the LN tree. A phylogenetic network of LN suggested that reticulation caused by hybridization is one of the major evolutionary processes for Pyrus species. Polytomies of the gene trees and star-like structure of cpDNA networks suggested rapid radiation is another major evolutionary process, especially for the occidental species. Pyrus calleryana and P. regelii were the earliest diverged Pyrus species. Two North African species, P. cordata, P. spinosa and P. betulaefolia were descendent of primitive stock Pyrus species and still share some common molecular characters. Southwestern China, where a large number of P. pashia populations are found, is probably the most important diversification center of Pyrus. More accessions and nuclear genes are needed for further understanding the evolutionary histories of Pyrus.