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Adaptation to Change. Donal T. Manahan Professor of Biological Sciences University of Southern California. Adaptation to Change. Genotype plus Environment = Phenotype Genetics = Change over longer time Physiology = Change over short time. Climate Change in the News a Lot.
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Adaptation to Change Donal T. Manahan Professor of Biological Sciences University of Southern California
Adaptation to Change Genotype plus Environment = Phenotype Genetics = Change over longer time Physiology = Change over short time
Warming of oceans: life history and trophic mismatch Comprehensive study of ~400 taxa, from 1958 to 2002. (>115,000 samples) Sir Alister Hardy Foundation for Ocean Science, The Laboratory, Citadel Hill, Plymouth, UK Impact of climate change on marine pelagic phenology and trophic mismatch. Edwards, M. and A.J. Richardson, 2004. Nature, 430: 881. Climate impact on plankton ecosystems in the Northeast Atlantic. Richardson, A.J. and D.S. Schoeman, 2004. Science, 305: 1609.
Trophic Match “Plant” “Animal” Amount Time
Trophic Mismatch “Phytoplankton” “Larvae” Amount Time
Complex Life Histories Physiology – The Science of “How Organisms Work”
The Larval Biology “Black Box”Food limitation, predation, transport, dispersal etc. Larval Mortality Recruitment <<1% Eggs
Genomics Physiology Complex Traits: Life Span Feeding, Metabolism Measure & Predict? Themes for Today’s Presentation Genetic Crosses Phenotype (Variation in Survival and Growth)
3 & 5 2 & 5 2 & 3 5 & 6 2 & 6 Larval families crossed 2 & 5 3 & 5 1 & 5 1 & 3 Up to a 4-times faster growth rate 3 & 5 2 & 5 2 & 3 0 5 10 15 20 Growth rate (µm day-1) Different growth rates in similar environment of food and temperature (N = 35 different larval families) Data from Pace et al., 2006 J. Exp. Mar. Biol. Ecol.
Large-scale Culturing Experiments (200-liter vessels x 20 units = 4,000 liters) ~2 million individuals of same larval family per culture vessel
Condition index - mass - volume feeding metabolism & excretion Particulate (algae) Dissolved nutrients (transport rate) Energy consumption - metabolic rate - growth efficiency - aerobic capacity (citrate synthase) - ion regulation (ATPase) Loss of ingested food - absorption efficiency Difference in slow and fast growing larvae No difference Physiological bases of growth differencesunder same environmental conditions Growth = [Energy In] minus [Energy Out] Data from Pace et al., 2006 J. Exp. Mar. Biol. Ecol.
Fast growing larvae possess higher size-specific feeding rates
Fast-growing larval families) Slow-growing larval families) Average feeding rate at 220 µm (N = 332) Fast-growers = 21.7 µl larva-1 h-1 ~ 2-times faster Slow-growers = 11.4 µl larva-1 h-1 Physiological scaling of ~2-fold higher feeding rates set genetically
Fast-growing larvae Slow-growing larvae 33 35 53 Similar size-specific metabolic ratesNot ‘simple’ reduction in rate
Fast-growing larvae Slow-growing larvae 55 22 25 Similar size-specific metabolic ratesNot ‘simple’ reduction in rate
Physiological regulation of differential growth rates • Feeding: ~ 50% of growth rate variation 2. Metabolic regulation: Not total metabolic rate, but differential energy allocation efficiency (mechanism?)
Protein synthesis Protein degradation Protein growth The high cost of growth (protein) From Pace and Manahan, 2006 J. Exp. Biol. (sea urchin larvae)
Feeding rate 50% 50% How to grow faster in the same environment? Metabolism: Protein depositional efficiency
Biological Variation[e.g., growth; size; feeding; physiological rates; etc.] Vast majority of adaptive traits show complex inheritance – i.e., likely many genes contributing to a complex trait Hard to unravel the connections between genes, complex traits, and adaptation.
♂ Line 3 ♂ Line 5 ♀ Line 3 5x3 3x3 ♀ Line 5 3x5 5x5 Genomic Analysis of Differential Growth Reciprocal cross between parental lines Larval families with differential growth ANOVA, P<0.05
Transcriptome analysis cDNAs cloned on beads (MegaCloneTM) Slow-growing Fast-growing Sequences read & counted (MPSS: Massively Parallel Signature SequencingTM) Shared genes Advantages of MPSS: High sensitivity ( 3 tpm.) No a priori sequence needed Gene ID by ‘signature sequence’ ‘Slow-growth genes’ ‘Fast-growth genes’ Brenner et al, 2000 Nature Biotech. 18:630
60% Matches to genes annotated in Gene Ontology Functional Category Protein Synthesis Chromosome Organization Electron Transport ATP Synthesis Endocytosis Protein Folding Regulation of Metabolism Response to Oxidative Stress Its more than environment, and its more than simple additive genetics 62% http://www.GeneOntology.org/
“Building the Organism” Developmental Biology (Egg to Larva) Requires 1000s of genes Growth Physiology (Variation in Size) Number of genes = ? 10? 100? 1,000? 10,000?
Food from the ocean – Hybrid animal protein production Worldwide production of C.gigas = 4.4 M metric tons ($3.7 billion) FAO Yearbook of Fishery Statistics, 2003
Genomics Physiology Physiological GenomicsDefine mechanisms of growth and survival based on known Phenotypic Contrasts Phenotype (Variation in Survival and Growth)
Recruitment: Population Connectivity and Dynamics, Species Management … RECRUITMENT BIOLOGY Ecology, Evolution Physiology, Biochemistry Cellular, Molecular Chemical Environment Nutritional; chemo-sensory Physical Environment Currents; hydrography