Abstract Detail

Population Genetics/Genomics

Linan, Alexander [1], Lowry, Porter II [2], Miller, Allison [3], Schatz, George [2], Sevathian, Jean Claude [4], Edwards, Christine [5].

Factors affecting the genetic diversity and implications for conservation in a clade of oceanic-island trees.

A wide range of biogeographic, life history, and anthropomorphic factors may potentially shape the genetic diversity of island-endemic trees. Oceanic island-endemic lineages have a unique evolutionary trajectory, resulting from their establishment through the introduction of one or a few individuals representing a genetic bottleneck. More recently, island endemics have come under threat due to human-mediated activities (i.e., habitat loss, invasive species) that often result in population declines and potentially, the loss of genetic diversity through factors associated with small population size, such as drift, inbreeding, and bottlenecks. However, tree species often possess life history traits such as outcrossing mechanisms, long lifespans, and a propensity for interspecific hybridization that may buffer against the loss of genetic variation due to population contractions. In this study, we conducted a comparative population genomic analysis of 13 Mascarene-endemic Diospyros (Ebenaceae) that share life-history characteristics, but vary in island colonization history and distribution, population size, and IUCN status. We sought to assess the relative importance of colonization history, rarity, and life-history characteristics in shaping genetic diversity and apply the results of population genetic assessments to inform conservation strategies for Mascarene Diospyros. We genotyped 328 individuals across the islands using 2b-RADseq, compared genetic diversity both among and within species, and assessed patterns of genetic structure. We found that the greatest variation in genetic diversity was explained by whether a species is a solitary island endemic or co-occurs with others on the same island, likely because interspecific hybridization was more frequent among co-occurring species, which has been shown to increase genetic diversity. We also found that genetic diversity was slightly lower in the critically endangered species, likely because of more severe genetic bottlenecks in species experiencing greater declines. Finally, we provide conservation recommendations on prioritizing populations to maximize the protection of genetic diversity within each species.

1 - Missouri Botanical Garden, 4344 Shaw Blvd, St. Louis, MO, 63110, United States
2 - Missouri Botanical Garden, Africa and Madagascar Department, 4344 Shaw Blvd., Saint Louis, MO, 63110, USA
3 - Saint Louis Univ./Danforth Plant Science Center, Biology, 3507 Laclede Avenue, Macelwane Hall, St. Louis, MO, 63110, United States
4 - Botanist, Sustainability Consultant and Landscape Care and Maintenance, Beau Bassin-Rose Hill, Plaines Wilhems District, Mauritius
5 - Missouri Botanical Garden, 4344 Shaw Ave., St. Louis, MO, 63110, United States

Keywords:
Ebenaceae
genetic diversity
Mauritius
Rodrigues
Réunion
genetic structure
RADseq
Marscarenes.

Presentation Type: Oral Paper
Session: PGG2, Population Genetics and Genomics II
Location: /
Date: Wednesday, July 21st, 2021
Time: 10:00 AM(EDT)
Number: PGG2001
Abstract ID:252
Candidate for Awards:Margaret Menzel Award