Evidence for the existence of a third, ecologically distinct morph of the anemone, <i>Actinia equina</i>

Quicke, Donald L. J.; Brace, R. C.

doi:10.1017/s0025315400030216

Cited by 21 publications

(35 citation statements)

References 3 publications

(8 reference statements)

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“…An examination of the relative abundance of Hk-i and PDC phenotypes in a large number of samples collected from around the British Isles (Quicke & Brace, 1984) has provided strong circumstantial evidence to show that heterozygotes for the identified gene complex occupy a position/niche on the shore which is intermediate between those occupied by the two homozygous genotypes. Previously though, two morphs only were identified , one possessing G-, H-or L-PDC and corresponding to the L morph as defined here, the other, typically displaying PDCs ranging from red to pink, and comprising the U and M morphs.…”

Section: Discussionmentioning

confidence: 99%

“…Quicke & Brace (1984) have proposed that these individuals may result from backcrossing between members of the heterozygous morph and one of the homozygotes. A different situation though, appears to exist at To-i: whereas the gene complex characteristic of the L morph appears to be fixed for the fast allele, that characteristic of the U morph appears to carry both alleles.…”

Section: Discussionmentioning

confidence: 99%

“…Quicke & Brace (1984) have recently provided indirect evidence to show that anemones, which display red or pink pedal discs and which are heterozygous for hexokinase, occupy a niche/habitat which is spatially intermediate between those occupied by the two homozygotes. We do not consider that the evidence amassed thus far concerning these genotypes is sufficient to justify the separation of A. equina into a number of distinct species.…”

Section: Introductionmentioning

confidence: 99%

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Littoral Distributions and Evidence For Differential Post-Settlement Selection of the Morphs of Actinia Equina

et al. 1985

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Examination of the intertidal distributions of isozyme and pedal colour phenotypes of Actinia equina L. has shown that anemones displaying column coloration ranging from red to brown, are divisible into three, ecologically distinct forms in Britain, which we currently interpret as being morphs of a single species. These are termed the upper (U), mid (M) and lower (L) shore morphs, which are relatively most abundant on the upper mid, lower mid and low shores, respectively; not all morphs are represented on some shores. The U, M and L morphs may be separated on the basis of their hexokinase and malate dehydrogenase phenotypes. The U morph is homozygous slow and fast respectively, the L morph is slow and fast respectively whilst the M morph is heterozygous at both loci. Data on linkage of pedal disc colour and alleles at a tetrazolium oxidase locus, and of an association between alleles at the hexokinase locus and those at an esterase locus, are given.Genotype frequencies of the populations of juveniles recolonizing two experimentally cleared areas at approximately mean tide level in N. Yorkshire, together with those of the original juvenile occupants, conform to Hardy-Weinberg expectations. The original adult population contained an excess of M individuals. This data is interpreted as evidence for post-settlement selection. The sharp discontinuities in morph frequencies with height, observed in transect surveys and on steeply sloping rock faces in N. Yorkshire, indicate that the selection pressures concerned are extremely strong.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Littoral Distributions and Evidence For Differential Post-Settlement Selection of the Morphs of Actinia Equina

et al. 1985

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“…those deviating from the expected frequency based on random assortment during recombination, due to the close proximity of groups of loci on a chromosome). The situation in A.equina is further complicated by the demonstration of distinct morphs (Quicke and Brace, 1984;Quicke et al, 1985) or cryptic species (Haylor, Thorpe and Carter, 1984) adapted to different intertidal levels and microhabitats, and relying to different extents on asexual reproduction. Values of the ratio approximating 1.0 are rare in most populations of A.tenebrosa, and values tend to be lower (asexual reproduction more common) on stable than on unstable shores (Ayre, 1984b).…”

Section: Population Structurementioning

confidence: 99%

A Functional Biology of Sea Anemones

Shick¹

1991

249

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in writing of the publishers, or in the case of reprographic reproduction only in accordance with the terms of the licences issued by the Copyright Licensing Agency in the UK, or in accordance with the terms of licences issued by the appropriate Reproduction Rights Organization outside the UK. Enquiries concerning reproduction outside the terms stated here should be sent to the publishers at the UK address printed on this page.The publisher makes no representation, express or implied, with regard to the accuracy of the information contained in this book and cannot accept any legal responsibility or liability for any errors or omissions that may be made. British Library Cataloguing in Publication DataShick, J. Malcolm A functional biology of sea anemones. 1. Sea anemones I. Title II. Series 593.6 ISBN 978-94-010-5365-5 ISBN 978-94-011-3080-6 (eBook)

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“…The majority of anemones at Burniston can be classified into one of the following six pedal disc colour (PDC) categories : dark red, DRd; light red, LRd; pink, P; grey, G; green, H; grey or green with radiating red or orange lines, L. The three categories, DRd, LRd and P have been collectively referred to in some of our other work as R Quicke & Brace, 1984).…”

Section: Pedal Disc Colour Classificationmentioning

confidence: 99%

Biochemical-Genetic and Acrorhagial Characteristics of Pedal Disc Colour Phenotypes of Actinia Equina

1985

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An examination has been made of pedal colour phenotypes exhibited by the three morphs of the anemone, Actinia equina L., which are distinguishable on the basis of allelic identity at two enzyme loci. The U (upper mid shore) and M (lower mid shore) morphs have pedal discs ranging in colour from red to pink, whereas the L (low shore) morph displays a grey to green pedal disc. Significant differences in the proportions of U and M morphs were found between samples of anemones having red and pink pedal discs, obtained from Burniston, N. Yorkshire, but these were not sufficiently clear cut to permit visual separation of the two morphs. Neither the pink nor red, pedal disc colour categories were comprised solely of anemones of one morph.A comparison of acrorhagial features (size, type, colour and number) between samples of anemones displaying various pedal disc colours, has shown that they are clearly divisible into three groups with respect to pedal coloration: (1) dark red; (2) light red and pink;(3) gr e y and green (with or without contrasting radial lines). In the absence of isozyme data relating to anemones possessing different acrorhagial features, it is not possible at present to state whether or not these characteristics will prove to be of assistance in visually distinguishing between the U and M morphs.It is cautioned that the differences discerned in characteristics could be related to, and modified by, the incidence of aggressive encounters within each of the pedal disc colour groups. I N T R O D U C T I O NPrevious work has shown that three ecologically disinct morphs can be identified amongst beadlet anemones, Actinia equina L., ranging in column coloration from red to brown (Quicke, Donoghue & Brace, 1983;Quicke & Brace, 1984;Quicke et al. 1985). Each is adapted to a different inter-tidal range, and is characterized by a multi-locus gene complex, which includes loci encoding a number of metabolically important enzymes, pedal disc coloration and probably strength of pedal attachment. They have been named the upper (U), mid (M) and lower (L) shore morphs, and are relatively most abundant on the upper mid, lower mid and low shores respectively. Members of the U morph are typically homozygous slow and fast at a hexokinase locus and a malate dehydrogenase locus respectively, whereas those of the L morph are typically homozygous for the other allele at each of these loci; M morph individuals are heterozygous at both.We have found that pedal disc coloration may be used to distinguish the majority of L morph individuals from members of the other two. L individuals

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Evidence for the existence of a third, ecologically distinct morph of the anemone, Actinia equina

Cited by 21 publications

References 3 publications

Littoral Distributions and Evidence For Differential Post-Settlement Selection of the Morphs of Actinia Equina

Littoral Distributions and Evidence For Differential Post-Settlement Selection of the Morphs of Actinia Equina

A Functional Biology of Sea Anemones

Biochemical-Genetic and Acrorhagial Characteristics of Pedal Disc Colour Phenotypes of Actinia Equina

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