Rejection of the genetic implications of the “Abundant Centre Hypothesis” in marine mussels
- Ntuli, Noxolo N, Nicastro, Katy R, Zardi, Gerardo I, Assis, Jorge, McQuaid, Christopher D, Teske, Peter R
- Authors: Ntuli, Noxolo N , Nicastro, Katy R , Zardi, Gerardo I , Assis, Jorge , McQuaid, Christopher D , Teske, Peter R
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444839 , vital:74302 , https://www.nature.com/articles/s41598-020-57474-0
- Description: The ‘Abundant-Centre Hypothesis’ is a well-established but controversial hypothesis stating that the abundance of a species is highest at the centre of its range and decreases towards the edges, where conditions are unfavourable. As genetic diversity depends on population size, edge populations are expected to show lower intra-population genetic diversity than core populations, while showing high inter-population genetic divergence. Here, the genetic implications of the Abundant-Centre Hypothesis were tested on two coastal mussels from South Africa that disperse by means of planktonic larvae, the native Perna perna and the invasive Mytilus galloprovincialis. Genetic structure was found within P. perna, which, together with evidence from Lagrangian particle simulations, points to significant reductions in gene flow between sites. Despite this, the expected diversity pattern between centre and edge populations was not found for either species. We conclude that the genetic predictions of the Abundant-Centre Hypothesis are unlikely to be met by high-dispersal species with large population sizes, and may only become evident in species with much lower levels of connectivity.
- Full Text:
- Date Issued: 2020
- Authors: Ntuli, Noxolo N , Nicastro, Katy R , Zardi, Gerardo I , Assis, Jorge , McQuaid, Christopher D , Teske, Peter R
- Date: 2020
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/444839 , vital:74302 , https://www.nature.com/articles/s41598-020-57474-0
- Description: The ‘Abundant-Centre Hypothesis’ is a well-established but controversial hypothesis stating that the abundance of a species is highest at the centre of its range and decreases towards the edges, where conditions are unfavourable. As genetic diversity depends on population size, edge populations are expected to show lower intra-population genetic diversity than core populations, while showing high inter-population genetic divergence. Here, the genetic implications of the Abundant-Centre Hypothesis were tested on two coastal mussels from South Africa that disperse by means of planktonic larvae, the native Perna perna and the invasive Mytilus galloprovincialis. Genetic structure was found within P. perna, which, together with evidence from Lagrangian particle simulations, points to significant reductions in gene flow between sites. Despite this, the expected diversity pattern between centre and edge populations was not found for either species. We conclude that the genetic predictions of the Abundant-Centre Hypothesis are unlikely to be met by high-dispersal species with large population sizes, and may only become evident in species with much lower levels of connectivity.
- Full Text:
- Date Issued: 2020
Two sides of the same coin: extinctions and originations across the Atlantic/Indian Ocean boundary as consequences of the same climate oscillation
- Teske, Peter R, Zardi, Gerardo I, McQuaid, Christopher D, Nicastro, Katy R
- Authors: Teske, Peter R , Zardi, Gerardo I , McQuaid, Christopher D , Nicastro, Katy R
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445547 , vital:74399 , https://doi.org/10.21425/F5FBG15591
- Description: Global climate change is correlated not only with variation in extinction rates, but also with speciation rates. However, few mechanisms have been proposed to explain how climate change may have driven the emergence of new evolutionary lineages that eventually became distinct species. Here, we discuss a model of range extension followed by divergence, in which the same climate oscillations that resulted in the extinction of coastal species across the Atlantic/Indian Ocean boundary in southwestern Africa also sowed the seeds of new biodiversity. We present evidence for range extensions and evolutionary divergence from both fossil and genetic data, but also point out the many challenges to the model that need to be addressed before its validity can be accepted.
- Full Text:
- Date Issued: 2013
- Authors: Teske, Peter R , Zardi, Gerardo I , McQuaid, Christopher D , Nicastro, Katy R
- Date: 2013
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445547 , vital:74399 , https://doi.org/10.21425/F5FBG15591
- Description: Global climate change is correlated not only with variation in extinction rates, but also with speciation rates. However, few mechanisms have been proposed to explain how climate change may have driven the emergence of new evolutionary lineages that eventually became distinct species. Here, we discuss a model of range extension followed by divergence, in which the same climate oscillations that resulted in the extinction of coastal species across the Atlantic/Indian Ocean boundary in southwestern Africa also sowed the seeds of new biodiversity. We present evidence for range extensions and evolutionary divergence from both fossil and genetic data, but also point out the many challenges to the model that need to be addressed before its validity can be accepted.
- Full Text:
- Date Issued: 2013
Coastal topography drives genetic structure in marine mussels
- Nicastro, Katy R, Zardi, Gerardo I, McQuaid, Christopher D, Teske, Peter R, Barker, Nigel P
- Authors: Nicastro, Katy R , Zardi, Gerardo I , McQuaid, Christopher D , Teske, Peter R , Barker, Nigel P
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445634 , vital:74409 , https://doi.org/10.3354/meps07607
- Description: Understanding population connectivity is fundamental to ecology, and, for sedentary organisms, connectivity is achieved through larval dispersal. We tested whether coastal topography influences genetic structure in Perna perna mussels by comparing populations inside bays and on the open coast. Higher hydrodynamic stress on the open coast produces higher mortality and thus genetic turnover. Populations on the open coast had fewer private haplotypes and less genetic endemism than those inside bays. Gene flow analysis showed that bays act as source populations, with greater migration rates out of bays than into them. Differences in genetic structure on scales of 10s of kilometres show that coastal configuration strongly affects selection, larval dispersal and haplotype diversity.
- Full Text: false
- Date Issued: 2008
- Authors: Nicastro, Katy R , Zardi, Gerardo I , McQuaid, Christopher D , Teske, Peter R , Barker, Nigel P
- Date: 2008
- Subjects: To be catalogued
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/445634 , vital:74409 , https://doi.org/10.3354/meps07607
- Description: Understanding population connectivity is fundamental to ecology, and, for sedentary organisms, connectivity is achieved through larval dispersal. We tested whether coastal topography influences genetic structure in Perna perna mussels by comparing populations inside bays and on the open coast. Higher hydrodynamic stress on the open coast produces higher mortality and thus genetic turnover. Populations on the open coast had fewer private haplotypes and less genetic endemism than those inside bays. Gene flow analysis showed that bays act as source populations, with greater migration rates out of bays than into them. Differences in genetic structure on scales of 10s of kilometres show that coastal configuration strongly affects selection, larval dispersal and haplotype diversity.
- Full Text: false
- Date Issued: 2008
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