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Genetic population structure in the Antarctic benthos: insights from the widespread amphipod, Orchomenella franklini

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posted on 2023-05-17, 13:44 authored by Helen BairdHelen Baird, Miller, KJ, Stark, JS
Currently there is very limited understanding of genetic population structure in the Antarctic benthos. We conducted one of the first studies of microsatellite variation in an Antarctic benthic invertebrate, using the ubiquitous amphipod Orchomenella franklini (Walker, 1903). Seven microsatellite loci were used to assess genetic structure on three spatial scales: sites (100 s of metres), locations (1–10 kilometres) and regions (1000 s of kilometres) sampled in East Antarctica at Casey and Davis stations. Considerable genetic diversity was revealed, which varied between the two regions and also between polluted and unpolluted sites. Genetic differentiation among all populations was highly significant (FST = 0.086, RST = 0.139, p<0.001) consistent with the brooding mode of development in O. franklini. Hierarchical AMOVA revealed that the majority of the genetic subdivision occurred across the largest geographical scale, with Nem≈1 suggesting insufficient gene flow to prevent independent evolution of the two regions, i.e., Casey and Davis are effectively isolated. Isolation by distance was detected at smaller scales and indicates that gene flow in O. franklini occurs primarily through stepping-stone dispersal. Three of the microsatellite loci showed signs of selection, providing evidence that localised adaptation may occur within the Antarctic benthos. These results provide insights into processes of speciation in Antarctic brooders, and will help inform the design of spatial management initiatives recently endorsed for the Antarctic benthos.

Funding

Holsworth Wildlife Research Endowment

History

Publication title

PloS One

Volume

7

Article number

e34363

Number

e34363

Pagination

1-10

ISSN

1932-6203

Department/School

Institute for Marine and Antarctic Studies

Publisher

Public Library of Science

Place of publication

USA

Rights statement

Licenced under Creative Commons Attribution 2.5 Generic (CC BY 2.5) http://creativecommons.org/licenses/by/2.5/

Repository Status

  • Open

Socio-economic Objectives

Marine biodiversity

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