Data and code from: Geographic isolation after admixture generates a distinct lineage in an Atlantic Forest bird
Data files
Abstract
Although traditionally viewed as opposing divergence, hybridization can have diverse evolutionary outcomes. Yet its role in lineage divergence remains unclear. To investigate this process, we examined the evolutionary history of the Black-cheeked Gnateater (Conopophaga melanops) from the Atlantic Forest of eastern Brazil. The central subspecies, C. m. perspicillata, exhibits plumage traits intermediate to northern and southern populations, raising the question of whether this pattern reflects isolation-by-distance, recent hybridization, or past admixture. Using genome-wide markers from sequencing of ultraconserved elements along with phenotypic data, we assessed genetic structure and trait variation across the species’ range. Our analyses reveal four population genetic clusters, with the two central clusters exhibiting clear signatures of historical admixture. Despite this admixture, central populations are genetically differentiated from northern and southern lineages and sing a distinct song, suggesting divergence following admixture or transgressive segregation. We propose that past hybridization followed by geographic isolation contributed to the formation of a divergent, reticulate lineage within the Black-cheeked Gnateater. This system provides an opportunity to investigate how gene flow and allopatric divergence interact to shape lineage diversity and offers a natural framework for testing the conditions under which reticulate lineages may emerge, persist, and diverge.
This repository contains the genetic, phenotypic, and bioacoustic data, alongside the R scripts, used to investigate the evolutionary history of the Black-cheeked Gnateater (Conopophaga melanops) in the following study:
Lima, R. D., et al. (2026). Geographic isolation after admixture generates a distinct lineage in an Atlantic Forest bird. Evolution, qpag069.
The dataset is divided into two compressed directories:
data.zip(containing raw and filtered genetic files, phenotypic trait data, and metadata).code.zip(containing R scripts used for all analyses and plots).
cono_raw.vcf: The raw, unfiltered variant call format (VCF) file containing 155,803 SNPs
generated from the UCE sequence capture.cono95MAC2.vcf: The filtered, linked SNP dataset (758 SNPs) retaining loci with 95% completeness and a Minor Allele Count (MAC) of 2. Used for PCA, Fst, and heterozygosity analyses.cono95MAC2_unlinked.vcf: The filtered, unlinked SNP dataset (553 SNPs), thinned to one SNP per 10,000 bp. Used for sNMF and EEMS analyses.nd2_cono.fasta: Alignment of the mitochondrial ND2 gene (1030 bp for 20 individuals) in FASTA format.nd2_cono.nex: The identical ND2 alignment formatted for NEXUS-based phylogenetic software.cono.gendist.txt: Pairwise genetic distance matrix used for specific phylogenetic network analyses.Conopophaga_genetic_samples.csv: Metadata for all genotyped individuals.- collection: Acronym of the institution housing the specimen.
- skin.number: Catalog number for the study skin voucher.
- tissue.number: Catalog number for the tissue sample.
- sample.code: Concatenated identifier combining the institution acronym and sample number.
- DNA.source: Material from which DNA was extracted (tissue or toepad).
- id: Unique identifier for the individual used in genetic analyses.
- has.snp.data: Indicates whether genome-wide nuclear SNP data were successfully generated for the individual (yes/no).
- has.mtdna.data: Indicates whether mitochondrial DNA data were successfully recovered for the individual (yes/no).
- author: Initials identifying the author who generated the sequence data.
- genbank.number: GenBank accession number for previously published sequence data.
- pop: Population assignment.
- locality: Geographic collection site, including country, state, and specific location.
- plot.order: Numeric value used to sort and order samples in data visualizations.
- latitude: Geographic latitude of the collection site in decimal degrees.
- longitude: Geographic longitude of the collection site in decimal degrees.
Conopophaga_plumage_data.csv: Plumage trait data.- sample: Unique identification number.
- group: Population assignment.
- sex: Biological sex of the individual ('m' for male, 'f' for female).
- state: Brazilian state where the specimen was collected.
- locality: Specific geographic collection site.
- year: Year the specimen was collected.
- latitude: Geographic latitude in decimal degrees.
- longitude: Geographic longitude in decimal degrees.
- m.forehead.width.mm: Continuous measurement of the male's black forehead band width in millimeters.
- m.breast.color: Categorical score for male breast pattern (0 = clearly defined gray breast band; 1 = fuzzy gray breast band; 2 = white central breast).
- m.back.color: Categorical score for male back color (0 = brown; 1 = grayish).
- f.crown.color: Categorical score for female crown color (0 = orange-brown; 1 = dull brown; 2 = olive-brown; 3 = grayish-olive).
- m.forehead.width.scaled: Scaled continuous value of the male forehead band width (ranging from 0 to 1).
- m.breast.color.scaled: Scaled value of the male breast pattern score (0 to 1).
- m.back.color.scaled: Scaled value of the male back color score (0 to 1).
- f.crown.color.scaled: Scaled value of the female crown color score (0 to 1).
Conopophaga_song_measurements.csv: Song trait data data.- sample: Catalog identifier for the audio source (e.g., WA for WikiAves, XC for xeno-canto, ML for Macaulay Library).
- location: Specific geographic location of the recording.
- latitude: Geographic latitude in decimal degrees.
- longitude: Geographic longitude in decimal degrees.
- phrase: Numeric index of the specific song phrase analyzed within the recording.
- phrase.id: Unique identifier for the analyzed phrase.
- group: Population assignment.
- total.duration: Total duration of the analyzed song phrase in seconds.
- n.notes: Total number of notes within the phrase.
- n.notes.1st.half: Number of notes in the first half of the phrase.
- n.notes.2nd.half: Number of notes in the second half of the phrase.
- pace: Overall song pace, measured as notes per second.
- pace.scaled: Scaled value of the overall pace (ranging from 0 to 1).
- pace.1st.half: Song pace in the first half of the phrase.
- pace.2nd.half: Song pace in the second half of the phrase.
- change.in.pace: Ratio indicating the change in pace between the second and first half.
- mean.peak.freq: Mean peak frequency of the entire phrase in Hertz (Hz).
- mean.peak.freq.1st.half: Mean peak frequency of the first half of the phrase (Hz).
- mean.peak.freq.2nd.half: Mean peak frequency of the second half of the phrase (Hz).
- change.in.freq: Ratio indicating the change in mean peak frequency between the second and first half.
Missing data are represented by empty cells in all .csv files.
Description of the data files in code.zip
Conopophaga_SNP_filtering_for_pop_gen_analyses.R: Script detailing the filtering steps applied tocono_raw.vcfto generate the linked and unlinked datasets.Conopophaga_allele_frequency_differences.R: Calculates allele frequency differences between populations.Conopophaga_Fst.R: Computes pairwise Fst among the identified genetic clusters.Conopophaga_PCA.R: Performs Principal Component Analysis on the linked SNP dataset.Conopophaga_DAPC.R: Executes Discriminant Analysis of Principal Components to assess cluster separation.Conopophaga_sNMF.R: Runs sparse Nonnegative Matrix Factorization for admixture estimation.Conopophaga_EEMS.R: Generates the Estimated Effective Migration Surface to visualize areas of high/low gene flow.Conopophaga_phylogenetic_network.R: Constructs distance-based phylogenetic networks.Conopophaga_triangle_and_heterozygosity_plots.R: Plots interclass heterozygosity against hybrid indices to identify hybrid classes and distinguish historical from recent admixture.Conopophaga_mitochondrial_distances.R: Calculates uncorrected pairwise distances from the ND2 alignment.Conopophaga_geographic_cline_plots.R: Plots genetic and phenotypic variation against latitude.Conopophaga_plumage.R: Analyzes geographic variation in male and female plumage traits.Conopophaga_song.R: Analyzes geographic variation in song.
