Introgression of mtDNA appears common in animals but the implications of acquiring a novel mitochondrial genome are not well known. This study investigates mito-genome introgression between the lizard species Urosaurus graciosus, a thermal specialist, and U. ornatus, a species that occupies a wider range of thermal environments. As ectotherms, their metabolic rate is strongly influenced by the thermal environment; with mitochondria being linked to metabolic rates, overall energy budgets could be impacted by introgression. I use mitochondrial gene trees, inferred from Bayesian analyses of Cyt-B and ND1 gene sequences, along with morphology and microsatellites from nineteen populations of these two species to address if the direction and location of mito-nuclear discordance match predictions of introgression resulting from past population expansions. MtDNA is expected to move from resident species into expanding or invading species. Second, does having a heterospecific form of mitochondria impact body size, a trait strongly associated with fitness? Multiple independent introgression events of historic origin were detected. All introgression was unidirectional with U. ornatus-type mtDNA found in U. graciosus parental type individuals. This result was consistent with population expansions detected in U. graciosus but not U. ornatus. Females with heterospecific mtDNA were significantly smaller than homospecific forms and heterospecific males had a different relationship of body mass to body length than those with homospecific mtDNA. These changes indicate a potential selective disadvantage for individuals with heterospecific mitochondria and are consistent with the theoretical expectation that deleterious alleles are more likely to persist in expanding populations.
Sampling locations and sample sizes.
Sampling locations and initial species designations are provided for each sampling location. Site name abbreviations correspond to Figure 3. Sample sizes are given for each sampling location with mtDNA given on the first line, microsatellites the second, scale morphology the third and the forth row has additional individuals from Haenel 2007 and a manuscript that is in preparation included in figure 1 and body size analyses.
1 Table S1 locations.docx
Arlequin input file microsatellites
Formatted input file of microsatellite data used in Arlequin.
Table S2 microsat_infileALL.arp
STRUCTURE input: microsatellites
STRUCTURE input file of microsatellite alleles.Seven Microsatellites are provided in columns. The first column has individual Ids.
Figure S3a project_data
STRUCTURE summary: deltaK
Graph of output of summary for STRUCTURE analyses. Evanno’s K and individual assignment probabilities were used to assess the best value of K (Evanno et al. 2005). This figure shows the results as DeltaK = mean(|L"(K)|)/sd(L(K)).
Figure S3b deltaK.png
Input file MrBayes mtDNA sequences.
Input file used to run phylogenetic analyses in MrBayes including mtDNA sequences. U. nigricaudus included as outgroup. MrBayes block included at bottom of the file.
4 Table S4a Uro16_07_25_Un_.txt
Summary of MrBayes analyses.
Table of summary of run from MrBayes phylogenetic analyses. This is the .mcmc output file.
4 Table S4b Uro16_07_25_Un_.txt.mcmc
Arlequin input U. orantus mtDNA sequences.
Arlequin input file for population genetic analyses of U. orantus mtDNA sequences. Includes geographic structure.
5 Table S5a infileND1CytB6_16_15Uo.arp
Arlequin input U. graciosus mtDNA sequences
Arlequin input file for population genetic analyses of U. graciosus mtDNA sequences. Includes geographic structure.
5 Table S5b infileND1CytB6_16_15Ug.arp
Parameter file for Bayesian Skyline Plot analyses U. ornatus
Parameter file for Bayesian Skyline Plot analyses of U. ornatus mtDNA sequence data in BEAST developed using BEAUti v1.8.2.
6 Table S6a UomtDNAcodon.xml
BSP analyses log file Uo mtDNA
BSP analyses log file generated in BEAST for U. ornatus mtDNA sequence data.
6 Table S6b UomtDNAcodon.log
Parameter file for BSP U. graciosus
Parameter file for Bayesian Skyline Plot analyses of U. graciosus mtDNA sequence data in BEAST developed using BEAUti v1.8.2.
6 Table S6c Uro16_07_25_UgcodonEBSP.xml
BSP analyses log file U. graciosus
BSP analyses log file generated in BEAST for U. graciosus mtDNA sequence data.
6 Table S6d Uro16_07_25_UgcodonEBSPcombined.log
Table of BAYESASS output
Migration Rates estimated with BAYESASS for U. graciosus and U. ornatus with lowest Bayesian deviances. Each species is a separate tab.
7 Table S7 BestBA3out.xlsx
Scale trait descriptions
Descriptions of scale morphology traits.
Table S8a scale trait descriptions.docx
Descriminant Function of Morphology
SAS code and data input to develop discriminatory function for scale characters of U. graciosus and U. ornatus. Column labels match Table S8a descriptions.
Table S8b SAS Descrime Program.txt
Lizard body size data
Body size data used to compare SVL of parental U. graciosus to heterospecific individuals and to analyze the relations of mass to SVL.
Table S9a bodysize.xlsx
Mass/SVL residuals ANOVA
ANOVA table generated in SAS comparing residuals of mass to SVL among different population groups.
Table S9b MassSVL residulasANOVA.txt