Reproductive isolation between lineages and its applied significance
- Background on speciation
- Phytophthora Lab
- Experiment 1- Prezygotic isolating mechanisms with Phytophthora
- Experiment 2 - GenBank Exercise with Phytophthora
- Supplies and Equipment - Phytophthora
- Hints for Instructors - Phytophthora
- Microbotryum Lab
- Biology of Microbotryum
- Experiment 1 - Prezygotic isolating mechanisms with
- Experiment 2 - GenBank Exercise with Microbotryum
- Supplies and Equipment - Microbotryum
- Hints for Instructors - Microbotryum
SPECIATION (the generation of independent lineages)
- Lineages can be considered independent of each other if they
do not exchange genetic information.
- Two possible mechanisms for limiting genetic exchange: geographical
barriers or biological barriers.
- Geographical barriers are often not permanent, and this
is ever more true in the modern world.
- Biological barriers can prevent the coalescence of lineages
when geographical barriers are removed.
- Biological barriers can be divided up by considering when
they take effect
- Pre-zygotic (pre-mating) barriers prevent the exchange
of gametes between individuals.
- Postzygotic barriers result in the death of the embryo
or sterility later in its development.
- Pre-zygotic barriers can result from behavioral mechanisms
or physiological mechanisms.
- Behavioral mechanisms include things such as courtship
- Physiological mechanisms involve the developmental or biochemical
- Applied aspects of species definitions
- Gene exchange between species: escape of transgenes, antibiotic
resistance, origin of crop plants, acquisition of disease resistance,
- Origin of new species
O’Brien, S. J. and Mayr, E. 1991. Bureaucratic mischief: recognizing
endangered species and subspecies.
Brasier, C. M., Cooke, D. E. L., and Duncan, J. M. 1999. Origin
of a new Phytophthora pathogen through
interspecific hybridization. Proc. Natl.
Acad. Sci. USA 96:5878-5883.
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