Population genetics and biology of deep-sea crustacea
Population genetics and biology of deep-sea crustacea
Starch gel electrophoresis was employed to discern the genetic population structure in four principal species of deep-sea Crustacea from the North Atlantic and Indian Oceans. The number of loci screened in each species varied from 8 to 20. Observed heterozygosity (Ho) was typically lower than expected. Values of Ho varied from 0.000 to 0.172, which are in the normal range of invertebrates and deep-sea Crustacea.
Allelic frequency data of the vent-endemic caridean shrimp Rimicaris exoculata indicate that all morphotypes of R. exoculata examined, from two hydrothermal vent fields (located along the Mid-Atlantic Ridge), including those previously interpreted as representing separate species, are conspecific. Conversely, genetic identity between a single putative specimen of Chorocaris fortunata and R. exoculata was high for intergeneric comparisons. Estimates of variance of allele frequencies among populations (FST) between sites were very low (mean FST = 0.001) indicating no significant genetic differentiation between populations separated by approximately 370 km.
The biology and genetics of populations of the majid crab Encephaloides armstrongi separated by depth were studied. The overall sex ratio was male-biased (p < 0.01). In both male and female E. armstrongi, individuals from a single population located at 150 m depth were significantly smaller than individuals at all other stations and were considered to represent a juvenile cohort. Additional, significant differences in length frequency were detected between male crabs from populations between 300 to 650 m depth. Six enzyme systems coding for eight loci for individuals were sampled from each population of E. armstrongi. Genetic identity (I) values between populations of E. armstrongi (I= 0.98-1.00) were typical of conspecific populations. For both male and female E. armstrongi significant genetic differentiation was detected between the population located at 150 m depth and all other populations. Analyses of FIS (The correlation between homologous alleles between individuals within local populations) and FST, excluding the 150 m population, indicated that for female E. armstrongi, in contrast to males, there was no significant structuring within or between populations. It is likely that E. armstrongi exhibits gender-biased dispersal and that the crabs collected between 300 m - 650 m depth formed spawning aggregations. This also explains the bias in sex ratio of individuals sampled in the present study.
University of Southampton
1998
Creasey, Simon Spencer
(1998)
Population genetics and biology of deep-sea crustacea.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
Starch gel electrophoresis was employed to discern the genetic population structure in four principal species of deep-sea Crustacea from the North Atlantic and Indian Oceans. The number of loci screened in each species varied from 8 to 20. Observed heterozygosity (Ho) was typically lower than expected. Values of Ho varied from 0.000 to 0.172, which are in the normal range of invertebrates and deep-sea Crustacea.
Allelic frequency data of the vent-endemic caridean shrimp Rimicaris exoculata indicate that all morphotypes of R. exoculata examined, from two hydrothermal vent fields (located along the Mid-Atlantic Ridge), including those previously interpreted as representing separate species, are conspecific. Conversely, genetic identity between a single putative specimen of Chorocaris fortunata and R. exoculata was high for intergeneric comparisons. Estimates of variance of allele frequencies among populations (FST) between sites were very low (mean FST = 0.001) indicating no significant genetic differentiation between populations separated by approximately 370 km.
The biology and genetics of populations of the majid crab Encephaloides armstrongi separated by depth were studied. The overall sex ratio was male-biased (p < 0.01). In both male and female E. armstrongi, individuals from a single population located at 150 m depth were significantly smaller than individuals at all other stations and were considered to represent a juvenile cohort. Additional, significant differences in length frequency were detected between male crabs from populations between 300 to 650 m depth. Six enzyme systems coding for eight loci for individuals were sampled from each population of E. armstrongi. Genetic identity (I) values between populations of E. armstrongi (I= 0.98-1.00) were typical of conspecific populations. For both male and female E. armstrongi significant genetic differentiation was detected between the population located at 150 m depth and all other populations. Analyses of FIS (The correlation between homologous alleles between individuals within local populations) and FST, excluding the 150 m population, indicated that for female E. armstrongi, in contrast to males, there was no significant structuring within or between populations. It is likely that E. armstrongi exhibits gender-biased dispersal and that the crabs collected between 300 m - 650 m depth formed spawning aggregations. This also explains the bias in sex ratio of individuals sampled in the present study.
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Published date: 1998
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Local EPrints ID: 463223
URI: http://eprints.soton.ac.uk/id/eprint/463223
PURE UUID: bb0e5dcd-04aa-4ade-8344-59ef23e99b00
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Date deposited: 04 Jul 2022 20:47
Last modified: 04 Jul 2022 20:47
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Author:
Simon Spencer Creasey
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