Effect of isolation on coat colour polymorphism of Polynesian rats in Island Southeast Asia and the Pacific

Populations of vertebrate species introduced onto islands regularly develop similar phenotypic changes, e.g., larger or smaller body size, shortened limbs, duller coats, as well as behavioural changes such as increased tameness and reduced flight-initiation distance. These changes overlap in part wi...

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Main Author: Alexandra A.E. van der Geer
Format: Article
Language:English
Published: PeerJ Inc. 2019-05-01
Series:PeerJ
Subjects:
Online Access:https://peerj.com/articles/6894.pdf
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author Alexandra A.E. van der Geer
author_facet Alexandra A.E. van der Geer
author_sort Alexandra A.E. van der Geer
collection DOAJ
description Populations of vertebrate species introduced onto islands regularly develop similar phenotypic changes, e.g., larger or smaller body size, shortened limbs, duller coats, as well as behavioural changes such as increased tameness and reduced flight-initiation distance. These changes overlap in part with those associated with the ‘domestication syndrome’, especially tameness and changes in coat patterns, and might indicate a similar neural crest involvement in the concurrent development of multiple phenotypic traits. Here I examine long-term data on free-living populations of wild Polynesian rats from seven mainland countries and 117 islands (n = 3,034), covering the species’ native and introduced range. Mainland populations showed no aberrant coat patterns, with the exception of one albino, whereas aberrant coat patterns were found in 12 island populations. Observed coat colour polymorphisms consisted of leucistic (including singular white patches), melanistic (darkly pigmented) and piebald (mixed) coat patterns. After isolation for at least seven centuries, wild Polynesian rat populations on islands seem to exhibit a trend towards a higher incidence of aberrant coat patterns. These phenotypic changes are here explained as a neutral, non-adaptive process, likely part of the ‘domestication syndrome’ (via the commensal pathway of domestication), in combination with genetic drift, little or no gene flow between the islands and/or the mainland and a relaxed selection (as a result of the weakening or removal of competitor/predator pressure) under commensality.
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spelling doaj.art-a46c94bffd9649c59ea0af841cd1735c2023-12-02T22:01:12ZengPeerJ Inc.PeerJ2167-83592019-05-017e689410.7717/peerj.6894Effect of isolation on coat colour polymorphism of Polynesian rats in Island Southeast Asia and the PacificAlexandra A.E. van der Geer0Naturalis Biodiversity Center, Leiden, NetherlandsPopulations of vertebrate species introduced onto islands regularly develop similar phenotypic changes, e.g., larger or smaller body size, shortened limbs, duller coats, as well as behavioural changes such as increased tameness and reduced flight-initiation distance. These changes overlap in part with those associated with the ‘domestication syndrome’, especially tameness and changes in coat patterns, and might indicate a similar neural crest involvement in the concurrent development of multiple phenotypic traits. Here I examine long-term data on free-living populations of wild Polynesian rats from seven mainland countries and 117 islands (n = 3,034), covering the species’ native and introduced range. Mainland populations showed no aberrant coat patterns, with the exception of one albino, whereas aberrant coat patterns were found in 12 island populations. Observed coat colour polymorphisms consisted of leucistic (including singular white patches), melanistic (darkly pigmented) and piebald (mixed) coat patterns. After isolation for at least seven centuries, wild Polynesian rat populations on islands seem to exhibit a trend towards a higher incidence of aberrant coat patterns. These phenotypic changes are here explained as a neutral, non-adaptive process, likely part of the ‘domestication syndrome’ (via the commensal pathway of domestication), in combination with genetic drift, little or no gene flow between the islands and/or the mainland and a relaxed selection (as a result of the weakening or removal of competitor/predator pressure) under commensality.https://peerj.com/articles/6894.pdfDomestication syndromeLeucismRattus exulansIsland syndromePiebaldMelanism
spellingShingle Alexandra A.E. van der Geer
Effect of isolation on coat colour polymorphism of Polynesian rats in Island Southeast Asia and the Pacific
PeerJ
Domestication syndrome
Leucism
Rattus exulans
Island syndrome
Piebald
Melanism
title Effect of isolation on coat colour polymorphism of Polynesian rats in Island Southeast Asia and the Pacific
title_full Effect of isolation on coat colour polymorphism of Polynesian rats in Island Southeast Asia and the Pacific
title_fullStr Effect of isolation on coat colour polymorphism of Polynesian rats in Island Southeast Asia and the Pacific
title_full_unstemmed Effect of isolation on coat colour polymorphism of Polynesian rats in Island Southeast Asia and the Pacific
title_short Effect of isolation on coat colour polymorphism of Polynesian rats in Island Southeast Asia and the Pacific
title_sort effect of isolation on coat colour polymorphism of polynesian rats in island southeast asia and the pacific
topic Domestication syndrome
Leucism
Rattus exulans
Island syndrome
Piebald
Melanism
url https://peerj.com/articles/6894.pdf
work_keys_str_mv AT alexandraaevandergeer effectofisolationoncoatcolourpolymorphismofpolynesianratsinislandsoutheastasiaandthepacific