Neotropical freshwater mussel taxa have been historically understudied compared to Nearctic species. This research project focused on molecular phylogenetics and evolution of Nephronaias tempisquensis collected from Cañas, Guanacaste Province, Costa Rica. Phylogenetic analysis of nuclear and mitochondrial genes confirmed the hypothesized membership of N. tempisquensis in the Popenaiadini tribe of the Ambleminae freshwater subfamily. We also determined that some of these N. tempisquensis specimens exhibited doubly uniparental inheritance (DUI), a fascinating deviation from the paradigm of the strict maternal inheritance (SMI) of mitochondrial DNA (mtDNA). Mussels exhibiting DUI contain two highly divergent sex-associated mtDNA genomes that are passed maternally and paternally, respectively. The male-transmitted (M-type) and female-transmitted (F-type) mtDNA genomes of mussels exhibiting DUI also contain highly distinct open reading frame genes (orfs). However, the evolution of hermaphroditism presents an interesting variation of DUI. The shift from a dioecious species exhibiting DUI to hermaphroditism is characterized by the loss of the M-type genome and the transformation of the F-type genome into an H-type genome. Previous research has explored the utility of F-type orf (F-orf) sequences in determining whether a population has recently transitioned or is in the process of transitioning to hermaphroditism by comparing the amino acid hydrophobicity profiles of the divergent F-orf and the hermaphroditic H-orf. Chapter 4 used this method to determine whether N. tempisquensis is exhibiting signs of the transition to hermaphroditism, however, no molecular evidence of such a transition was observed. F-orf divergence trends were also compared among taxa from the Ambleminae subfamily and the previously studied Unioninae subfamily to elucidate any trends in patterns of molecular evolution within and between these taxonomic assemblages.
Call Number
LE3 .A278 2024
Date Issued
2024
Supervisor
Degree Name
Master of Science
Degree Level
Masters
Degree Discipline
Affiliation
Abstract
Publisher
Acadia University