-------- Original Message --------
Subject: Re: Cryptic in genetics
Date: Mon, 26 May 2008 16:56:39 -0700 (PDT)
From: Michael A. Bell <[EMAIL PROTECTED]>
Reply-To: [EMAIL PROTECTED]
To: morphmet@morphometrics.org
CC: morphmet <morphmet@morphometrics.org>
References: <[EMAIL PROTECTED]>
Pablo -- Here is a nice example of a phenotypically distinctive biological
species that were indistinguishable using genetic markers. (I should say
at the outset that I don't have time to go back and check these papers, so
anything you read below needs to be verified. However, it is probably
right, except for the details.)
First, Blouw and Hagen (1990) reported on a marine threespine stickleback
that has distinctive white male nuptial coloration and reproductive
behavior compared to the more widespread threespine stickleback
(Gasterosteus aculeatus), in which males develop red and blue coloration.
The endemic from Nova Scotia is commonly called the "white sticklebak" but
has never been described as a taxon. However, Blouw and Hagen (1990)
showed that it is phenotypically divergent, most markedly in male nuptial
coloration and reproductive behavior, but also for some meristic traits.
They also presented evidence for strong positive assortative mating. The
paper is
Blouw, D. M. and D. W. Hagen. 1990. Breeding ecology and evidence of
reproductive isolation of a widespread stickleabk fish (Gasterosteidae) in
Nova Scotia, Canada. Biol. J. Linn. Soc 39:195-217.
Blouw and others published additional papers on divergent reproductive
biology of the "white" stickleback and the common, red, marine threespine
stickleback, including:
McDonald, J. F., J. F. Bekkers,S. M. MacIsaac, and D. M. Blouw. 1995.
Intertidal breeding and aerial development of embryos of a stickleback
fish (Gasterosteus). Behaviour 132:1183-1206.
McDonald, J. F., S. M. MacIsaac, J. F. Bekkers, and D. M. Blouw. 1995.
Experiments on embryo survivorship, habitat selection, and competitive
ability of a stickleback fish (Gasterosteus) which nests in the rocky
intertidal zone. Behaviour 132:1207-1221.
However, Haglund et al. (1990) examined allozyme variation in pairs of
allopatric and sympatric white and common red stickleback and found that
the allopatric whites and reds were as different from each other for
allozyme frequencies as the sympatric whites and reds were. They
questioned whether the white species was a separate entity or simply a
morph. In a later review paper (Buth and Haglund 1994) they stated that
the allozyme data provided no evidence supporting the conclusion that the
white and red stickleback are different species. Fair enough, but the
phenotypic data do.
Oddly enough, Blouw found himself on both sides of this issue in a pair of
papers published the same year, but I believe he favored the view that the
white stickleabck is a separate species, and susbsequent reviews (except
for one by Haglund and Buth 1994) have all favored the view that the white
and sympatric red sticklebacks are separate species.
There have been three reviews concerning biological species within the
threespine stickleback complex (McPhail 1994; McKinnon and Rundle 2002;
and Boughman 2007), and the most recent review is
Boughman, J. W. 2007. Speciation in sticklebacks. Pp. 83-126 in S.
Ostlund-Nilsson, I. Mayer, and F. A. Huntingford (eds.) Biology of the
Threespined Stickleback. CRC Press, Boca Raton.
There are also several pairs of trophically divergent biological species
of threespine stickleback in a few lakes in British Columbia. Members of
each pair also differ from each other for male nuptial coloration and body
size, and they mate positively assortatively. They are discussed in
Boughman (2007) and the other reviews, which she cited.
Two papers by E. B. Taylor and J. D. McPhail (1999, 2000) used mtDNA and
then microsatellites to look for evidence on their relationships. Although
similar morphotypes from different lakes did not form a clade using DNA
variation, and each morphotype was usually more closely related to
allopatric populations than to the phenotypically divergent stickleback
from the same lake, there MAY have been one or two pairs in which members
of the pairs were more similar to each other than to populations outside
the lake for DNA variation. I am relating this from memory, so please
check the details.
More recently, Gow et al. (2006, 2007) have studied hybridization rates
and selection against hybrids some of the lacustrine stickleback species
pairs using microsatellites. Hybridization between contrasting morphotypes
within the lakes could cause them to be similar for quasineutral genetic
traits and cause them to cluster on a tree. The Gow et al. papers are
Gow, J. L., C. L. Peichel, and E. B. Taylor. 2006. Contrasting
hybridization rates betwen sympatric three-spined stickleabks highlight
the fragility of reproductive barriers between evolutionarily young
species. Molecular Ecology 15:739-752.
Gow, J. L., C. L. Peichel, and E. B. Taylor. 2007. Ecological selection
against hybrids in natural populations of sympatric threespine
sticklebacks. Journal of Evolutionary Biology 20:2173-2180.
Both of the Gow et al. papers cite the Taylor and McPhail papers. In
addition, these stickleback species pairs have been used extensively in
Dolph Schluter's lab at the University of British Columbia, and additional
papers on them can be found on Dolph's website.
In general threespine stickleback provide a good source of examples of
populations that have diverged phenotypically but may not have diverged
for quasineutral molecular genetic markers. Simiarly, other postglacial
fish populations may have diverged markedly for trophic traits in
depauperate fish communities without much divergence for molecular-genetic
traits. Schluter, Taylor, and I (with Chris Andrews) have written on some
aspects of postglacial phenotypic divergence of boreal freshwater fishes,
as well, and Taylor's review is most likely to contain the genetic
information you are interested in.
-- Mike Bell
-------- Original Message --------
Subject: Re: Cryptic in genetics
Date: Thu, 22 May 2008 07:13:12 -0700 (PDT)
From: Pedro Cordeiro Estrela <[EMAIL PROTECTED]>
To: morphmet@morphometrics.org
Dear Pablo,
The example you are trying to find is in fact difficult because few
systematist who use different
criteria to define species will recognize a species (as a biological
entity) based on
morphological difference if genetic markers say the contrary. You
probably already read it, but
Kevin de Queiroz articles on species concepts and criteria are specially
enlightening (see bibtex
files at the end of the e-mail).
One noteworthy exception is when specific character divergence produces
reproductive isolation.
You might look into the Drosophila melanogaster subgroup for some
examples on the evolution of
genitalia. You might also look at the Ensatina complex. Although these
salamanders are recognized
as subspecies they are morphologically distinct.
hope it helped!
pedro
@INBOOK{Queiroz1998,
chapter = {5: The general Lineage Concept of Species, Species
Criteria, and
the Process of Speciation},
pages = {57-75},
title = {Endless Forms: species and speciation},
publisher = {Oxford University Press},
year = {1998},
editor = {Daniel J. Howard and Stewart H. Berlocher},
author = {de Queiroz, Kevin},
address = {New York, Oxford},
}
@ARTICLE{Queiroz2005,
author = {Kevin de Queiroz},
title = {Ernst Mayr and the modern concept of species.},
journal = {Proc Natl Acad Sci U S A},
year = {2005},
volume = {102 Suppl 1},
pages = {6600--6607},
month = {May},
abstract = {Ernst Mayr played a central role in the establishment of
the general
concept of species as metapopulation lineages, and he is the author
of one of the most popular of the numerous alternative definitions
of the species category. Reconciliation of incompatible species
definitions
and the development of a unified species concept require rejecting
the interpretation of various contingent properties of metapopulation
lineages, including intrinsic reproductive isolation in Mayr's
definition,
as necessary properties of species. On the other hand, the general
concept of species as metapopulation lineages advocated by Mayr forms
the foundation of this reconciliation, which follows from a corollary
of that concept also advocated by Mayr: the proposition that the
species is a fundamental category of biological organization. Although
the general metapopulation lineage species concept and Mayr's popular
species definition are commonly confused under the name "the biological
species concept," they are more or less clearly distinguished in
Mayr's early writings on the subject. Virtually all modern concepts
and definitions of the species category, not only those that require
intrinsic reproductive isolation, are to be considered biological
according to the criterion proposed by Mayr. Definitions of the species
category that identify a particular contingent property of
metapopulation
lineages (including intrinsic reproductive isolation) as a necessary
property of species reduce the number of metapopulation lineages
that are to be recognized taxonomically as species, but they cause
conflicts among alternative species definitions and compromise the
status of the species as a basic category of biological organization.},
doi = {10.1073/pnas.0502030102},
keywords = {Animals; Classification; Evolution; Models, Biological;
Species Specificity},
pii = {0502030102},
pmid = {15851674},
timestamp = {2007.07.09},
url = {http://dx.doi.org/10.1073/pnas.0502030102}
}
--- morphmet <[EMAIL PROTECTED]> wrote:
-------- Original Message --------
Subject: Cryptic in genetics
Date: Wed, 21 May 2008 15:41:45 -0400
From: [EMAIL PROTECTED]
To: morphmet <[EMAIL PROTECTED]>
References: <[EMAIL PROTECTED]>
Dear colleagues,
Besides the problem behind species concepts and aesthetic
(non-scientific) values for particular kinds of phylogenetic and
taxonomic characters, I am currently searching for published examples
where the species is cryptic from the genetic perspective but
recognizable (different) from the morphological perspective. This is a
counter-current example which is apparently very difficult to find.
An interesting example is the evidence presented by Jeffrey Schwartz on
his book: "The Red Ape: Orangutans and Human Origins" where he contests
current genetic evidence upon the common origin shared by chimps and
humans, arguing instead for the orangutan.
I will appreciate any published studies suggesting morphological
evidence for species lineage independence (i.e. species) opposing
genetic evidence of single lineages (genetically cryptic).
Thanks
Pablo
Pablo Jarrin
Ph. D. candidate
Dept. of Biology / Boston University
M. A. Ecology Behavior and Evolution
Boston Univ.
Director
Yasuni Research Station
Escuela de Ciencias Biol�gicas
Pont. Univ. Cat�lica del Ecuador.
--
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For more information visit http://www.morphometrics.org
_______________________________________________________
Pedro Cordeiro Estrela
Dr.Sc.
Departamento de Genetica - Universidade Federal do Rio Grande do Sul
Campus do Vale - Bloco III
Av. Bento Gon�alves, 9500 - Agronomia
Porto Alegre, RS 91501-970 / Caixa Postal 15.053
Brasil.
TEL: +55 (51) 3308.6726
(cod. Porto Alegre)
________________________________________________________
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For more information visit http://www.morphometrics.org
Michael A. Bell, Professor
Department of Ecology and Evolution
Stony Brook University
Stony Brook, NY 11794-5245, USA
Phone:1-631-632-8574. Fax: 1-631-689-6682
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