Abstract Detail

Comparative Genomics/Transcriptomics

Valencia, Janice  [1], Neubig, Kurt [2], Whitten, William [3].

Variation in evolutionary rates across genomes in orchids.

Understanding evolution at the molecular level is one of the main goals in systematic biology today. Rates of nucleotide substitutions hold the key to the evolutionary history that gave rise to the organisms that survive today. Relatively few studies have addressed differences in the evolutionary rates in plants using plastid and mitochondrial genomes. Orchidaceae, with 110 million years of divergence as a lineage, a variety of life history traits, and a foundational phylogenetic framework, constitute a useful study group to analyze the patterns of the molecular evolution and their possible causes. Here, we compare nucleotide substitution rates for genes representing both plastomes and chondriomes in orchids. We also evaluate the substitution rate of repeated and single regions, coding and non-coding regions, and dN/dS (substitutional rates). Sequences were gathered by genome skimming 75 taxa on an Illumina HiSeqX that provided ca. 10 million, 150 bp paired-end reads per sample. Genes were targeted by a combination of reference and de novo assemblies in Geneious -R10 package, and comparisons were made using the relative likelihood ratio test. We show that sequences differ in their rates within and between each genome, likely due to the different types of evolutionary pressures to which they were subjected. Our phylogenetic results will provide a context to understand the fundamental processes that drive the generation and fixation of molecular changes.

1 - Southern Illinois University , Plant Biology Department, 1125 Lincoln Dr., Carbondale, IL, 62901, United States
2 - Southern Illinois University, Dept Of Plant Biology, 1125 Lincoln Dr., Life Science II, Room 420, Carbondale, IL, 62901, United States
3 - Florida Museum Of Natural History, Po Box 117800, 1659 Museum Road, Gainesville, FL, 32611, United States

Keywords:
none specified

Presentation Type: Oral Paper
Session: 25, Comparative Genomics and Transcriptomics II
Location: 102/Mayo Civic Center
Date: Tuesday, July 24th, 2018
Time: 4:00 PM
Number: 25012
Abstract ID:908
Candidate for Awards:None