Title: Evolution of Sympatric Color Polymorphism in the California Clingfish, Gobiesox rhessodon
1Evolution of Sympatric Color Polymorphism in the
California Clingfish, Gobiesox rhessodon
2Intro to G. rhessodon
- San Bartolome Bay, Baja California to Pismo
Beach, California - 3 sympatric color morphs (orange, brown, gray)
- Small size, simple diet could make them good lab
animals
Pismo
San Bartolome Bay
3Nest guarding
Lifecycle
Adult Life in the Intertidal to 11 m.
Pectoral suction cup
4Questions
- Are the 3 color morphs really all one species?
If yes, can any genetic divergence be detected? - What forces are sustaining the 3 forms?
5Project Outline
- Sequencing - look for cryptic species or signs of
speciation through sequence divergence - Laboratory Crosses - do we see hybrid breakdown
or epistasis? - Mate Choice Experiments - assortative mating
present?
6Sequencing
- Sequence fast evolving mt. locus, like CR, from
many individuals of brown, gray, and orange
morphs - Analyze using program like Sequencher
- Measure sequence divergence
7Lab Crosses
- Mate gray-gray, brown-brown, orange-orange for F1
generation - Cross gray-brown, orange-brown, etc. for F1
generation - Compare different crosses for both phenotype,
survivorship, and viability
If viability differences are seen, we could study
the genes involved in speciation process.
8Mate Choice
Control for fish size and observe, count mating
behaviors towards each color female
9Adjust for female preference
Assortative mating present?
10Summary
- Sequence data will show us whether or not 3 color
morphs have diverged - Lab crosses will show us if hybrid breakdown or
decreased survivorship exists (could provide new
model to study process of genetic divergence) - Mate choice experiments can show us whether
assortative mating seems to play a role (this can
result in sympatric speciation)
These all investigate in-house forces
11Alternative Explanations
- 1. Negative frequency-dependent selection,
where rare types have higher survival rates - 2. Search image formation in predators
These are both predator-induced alternatives and
are difficult to quantify.
12References
- Allen, L. G. (1983) Larval development of the
northern clingfish, Gobiesox-maeandricus.
Copeia. 2, 551-554. - Briggs, J. C. (1955) A monograph of the
clingfishes. Stanford Ichthyology Bulletin. 6,
1-224. - Punzalan, D., et al. (2005) Perceptual processes
and the maintenance of polymorphism through
frequency-dependent predation. Evolutionary
Ecology. 19, 303-320. - Seehausen, O., et al. (1999) Color Polymorphism
and sex ratio distortion in a cichlid fish as an
incipient stage in sympatric speciation by sexual
selection. Ecology Letters. 2, 367-378.