The intertidal copepod Tigriopus californicus was used as a model organism to look at effects of crossing distance on fitness and investigate the genetic mechanisms responsible. Crosses were conducted between 12 pairs populations spanning broad range both geographic (5 m 2007 km) (0.2% 22.3% sequence divergence for 606‐bp segment mitochondrial COI gene). For each pair populations, three components (hatching number, survivorship metamorphosis number) measured in up 16 cohorts including...

Abstract The copepod Tigriopus californicus shows extensive population divergence and is becoming a model for understanding allopatric differentiation the early stages of speciation. Here, we report high-quality reference genome one (~190 megabases across 12 scaffolds, ~15,500 protein-coding genes). Comparison with other arthropods reveals 2,526 genes presumed to be specific T. , an apparent proliferation involved in ion transport receptor activity. Beyond population, re-sequenced genomes...

Abstract Previous studies of the intertidal copepod Tigriopus californicus revealed one highest levels mitochondrial DNA differentiation ever reported among conspecific populations. The present study extends geographical sampling northward, adding populations from northern California to south‐east Alaska. phylogeny for entire species range, based on cytochrome oxidase I sequences a total 49 individuals 27 populations, again shows extreme (up 23%). However, Oregon northwards appear be derived...

Abstract: Hybridization between populations may cause either increased fitness ( “hybrid vigor” ) or decreased “outbreeding depression” ). Translocation therefore in some cases be a successful means of combating genetic erosion and preserving evolutionary potential, whereas other it make the situation worse by inducing outbreeding depression. Because distance alone is poor predictor success failure hybridization, we developed computer model ELAB to explore factors affecting consequences...

The respiratory enzyme cytochrome c oxidase (COX) is composed of subunits encoded by both nuclear and mitochondrial genes; thus, COX activity reflects, to some extent, the coordinated function two genomes. Because extensive mtDNA differentiation exists between populations copepod Tigriopus californicus, we hypothesized that laboratory hybridizations disrupt natural combinations genes might negatively impact activity. Although experimental results varied greatly among different crosses,...

Physiological phenotypes are the result of coordinated function many genes, some which may be differentiated between conspecific populations. Within any one population, natural selection will favor evolution a coadapted set alleles optimizes physiological performance and reproductive success. The existence such gene complexes assessed by assaying interpopulation hybrids: inferior hybrids suggests that allelic combinations present in parental populations coadapted. This approach has been used...

Journal Article MOLECULAR AND QUANTITATIVE TRAIT VARIATION WITHIN AMONG POPULATIONS OF THE INTERTIDAL COPEPOD TIGRIOPUS CALIFORNICUS Get access Suzanne Edmands, Edmands Department of Biological Sciences, University Southern California, Los Angeles, California 90007Department 90007 E‐mail: sedmands@usc.edu Search for other works by this author on: Oxford Academic Google Scholar J. Scott Harrison jharriso@usc.edu Evolution, Volume 57, Issue 10, 1 October 2003, Pages 2277–2285,...

Crosses between populations of the copepod Tigriopus californicus typically result in outbreeding depression. In this study, replicate hybrid were initiated with first generation backcross hybrids two genetically distinct from California: Royal Palms (RP) and San Diego (SD). Reciprocal F1 backcrossed to SD, resulting expected starting frequencies 25% RP/75% SD nuclear genes on either a pure RP cytoplasmic or background. After 1 year hybridization (up 15 generations), seven microsatellite...

Abstract Aim Previous work on the tidepool copepod Tigriopus californicus revealed a curious case of incipient speciation at southern end species' range in Baja California, Mexico. The present study expands geography this pattern and tests for congruence between reproductive phylogenetic patterns. Location Pacific coast North America, from central California to south‐eastern Alaska (27–57° N), including full T. . Methods Primary techniques included mating experiments (> 4000 crosses),...

Local adaptation has been understudied in marine systems, but might be expected to pronounced the tidepool copepod Tigriopus californicus, which a broad geographic range and extremely restricted dispersal. Tolerance temperature salinity was assessed 14 populations over 20° latitudinal range. Adaptive differentiation found at scales as low 5.6 km. Latitudinal clines were significant, with northern being more tolerant of less high salinity. Both tolerance closely associated long-term thermal...

Genetic interactions within hybrids influence their overall fitness. Understanding the details of these can improve our understanding speciation. One experimental approach is to investigate deviations from Mendelian expectations (segregation distortion) in inheritance mapped genetic markers. In this study, we used copepod Tigriopus californicus, a species which exhibits high divergence between populations and general pattern reduced fitness F2 interpopulation hybrids. Previous studies have...

Sex-determining systems are remarkably diverse and may evolve rapidly. Polygenic sex-determination predicted to be transient evolutionarily unstable, yet examples have been reported across a range of taxa. Here, we provide the first direct evidence polygenic sex determination in Tigriopus californicus, harpacticoid copepod with no heteromorphic chromosomes. Using genetically distinct inbred lines selected for male- female-biased clutches, generated genetic map 39 SNPs 12 Quantitative trait...

Introgressive hybridization between genetically divergent populations is an important evolutionary process. The degree to which repeated events the same parental taxa lead similar genomic outcomes unknown. This study addressed this question by following trajectories of replicate hybrid swarms copepod Tigriopus californicus over many generations free mating. Swarm composition was determined both differential reproductive success founder individuals and subsequent selection on genotypes. For...