Abstract Detail

Systematics

Xie, Jianguang [1], Diaz, Thomas [2], Henkins, Brittany [3], Zou, Yutong [3], Li, Jianhua [4].

Recent pervasive chloroplast captures in hazelnuts (Corylus L., Betulaceae).

Phylogenetic inference has been done based on various data sources from morphology to molecules and a congruence of phylogenies from different data suggests that true phylogenetic relationships have been inferred with high confidence. However, in many cases different data may support different phylogenies due to lack of informative characters or the potential existence of paralogy, incomplete lineage sorting, horizontal gene transfer, and hybridization. Numerous studies have shown that chloroplast capture may be a major source for incongruent nuclear and plastid phylogenies in many angiosperm taxa. Nevertheless the timing and biological significance of chloroplast captures have not been explored in depth. Corylus is a Northern Hemisphere woody plant genus with a disjunction distribution between eastern Asia, eastern Himalayas, Central Asia, Europe, and North America. Phylogenetic trees from nuclear and plastid genes and genomes revealed distinct and strongly supported incongruent relationships among species of Corylus. In this study, we used low copy nuclear genes and plastid and mitochondrial genomes to test the conflicting phylogenies and explored the timing and significance of the ancient and current hybridization and introgression. There are four major clades in the genus corresponding to the four sections that have been proposed based on morphology and nuclear data. Plastid sequence data, however, did not support the sections; instead, they generally demonstrated geographic structures. When chloroplast capture happened between a resident and an invading species, the direction is most likely from the former to the latter. However, when the capture is present among sympatric species, the direction may be bidirectional. This is apparently consistent with recent crossing experiments. Therefore, we speculated that the pattern might demonstrate the maternal effects on the offspring; but the adaptive mechanism remains to be studied.

1 - South China Agricultural University, College of Life Sciences, Guangzhou, Guangdong, China
2 - Hope College, Biology, 35 E 12th St., Holland, MI, 49423, USA
3 - Hope College, 35 E 12th St., Holland, MI, 49423, United States
4 - 35 E 12th Street, Holland, MI, 49423, United States

Keywords:
Corylus
plastome
Mitochondrial genome
chloroplast capture
hybridization.

Presentation Type: Oral Paper
Session: SYS2, Systematics II: Rosids part B to Basal Asterids
Location: Virtual/Virtual
Date: Tuesday, July 28th, 2020
Time: 1:15 PM
Number: SYS2004
Abstract ID:302
Candidate for Awards:None