Abstract Detail

Genomics / Proteomics

Walter, Lauren [1], Livshultz, Tatyana [2], Straub, Shannon C.K. [3].

Comparative genomic analysis of Apocynaceae plastomes: Pseudogenes, repeat content, and molecular evolution.

Plant plastomes are highly conserved in their size, organization, and gene content. Plastomes of various species of Apocynaceae have been shown to vary in their conservation of these aspects, especially within Asclepiadoideae. This subtribe shares evidence of a mitochondrial genome to plastome horizontal transfer, as well as loss of several genes, including accD and clpP, in several species. For this study plastomes were newly sequenced and characterized for five species of Apocynaceae: Aspidosperma cruentum, Carissa ovata, Carissa spinarum, Haplophyton crooksii, and Mandevilla × amabilis. These plastomes were characterized in a comparative study that also included 23 other species of Apocynaceae already in GenBank, as well as plastomes of two other species of Gentianales. Genome size, organization, gene content, and repeat content were analyzed, and phylogenetic analyses of individual genes were conducted in order to detect increased rates of molecular evolution in various species. The newly sequenced plastomes ranged in size from 154,057 bp in C. ovata to 159,700 bp in A. cruentum. The organization and gene content of A. cruentum, H. crooksii, and M. × amabilis were highly conserved compared to other Apocynaceae and flowering plant plastomes. However, both Carissa plastomes showed evidence of pseudogenization of accD, indicating loss of this gene in their common ancestor. These plastomes also had the highest repeat content of the newly sequenced plastomes. The repeat content was comparable to that observed in Eustegia minuta, which has lost multiple ndh genes to pseudogenization, but still less than that observed in Asclepias speices, which have pseudogenized copies of accD, clpP, ycf1, and ycf2. These observations support the hypothesis that there may be a correlation between repeat content and rate of molecular evolution, and further illustrate that as more plastomes are sequenced, more exceptions to the rule are uncovered.

1 - Hobart and William Smith Colleges, Department of Biology, 300 Pulteney St., Geneva, NY, 14456, USA
2 - Drexel University, Biodiversity Earth and Environmental Sciences, Academy Of Natural Sciences, 1900 Benjamin Franklin Parkway, Philadelphia, Pennsylvania, 19103, United States
3 - Hobart and William Smith Colleges, Department of Biology, 300 Pulteney Street, Geneva, NY, 14456, USA

Keywords:
Apocynaceae
Carissa
Plastome
accD.

Presentation Type: Poster
Session: P, Genomics/Proteomics Posters
Location: Exhibit Hall/Savannah International Trade and Convention Center
Date: Monday, August 1st, 2016
Time: 5:30 PM This poster will be presented at 5:30 pm. The Poster Session runs from 5:30 pm to 7:00 pm. Posters with odd poster numbers are presented at 5:30 pm, and posters with even poster numbers are presented at 6:15 pm.
Number: PGP009
Abstract ID:792
Candidate for Awards:Genetics Section Poster Award