Contact zones reveal restricted introgression despite frequent hybridization across a recent lizard radiation

Introgression — the exchange of genetic material through hybridization — is now recognized as common among animal species. The extent of introgression, however, can vary considerably even when it occurs: for example, introgression can be geographically restricted or so pervasive that populations merge. Such variation highlights the importance of understanding the factors mediating introgression. Here we used genome-wide SNP data to assess hybridization and introgression at 32 contact zones, comprising 21 phylogenetic independent contrasts across a recent lizard radiation (Heteronotia). We then tested the relationship between the extent of introgression (average admixture at contact zones) and genomic divergence across independent contrasts. Early-generation hybrids were detected at contact zones spanning the range of genomic divergence included here. Despite this, we found that introgression is remarkably rare and, when observed, geographically restricted. Only the two most genomically ..., , , # Data from: Contact zones reveal restricted introgression despite frequent hybridization across a recent lizard radiation

[https://doi.org/10.5061/dryad.prr4xgxx6](https://doi.org/10.5061/dryad.prr4xgxx6)

## Description of the data and file structure

Three folders are included here, the contents of each of which are outlined. The R scripts to accompany these are available via Zenodo (see link on the respective Dryad page).

### Files and variables

#### File: mtDNA\_data.zip

**Description:** This folder simply contains the ND2 mitochondrial DNA sequence alignment in fasta format (hets_nd2.fasta) along with the respective partition file (hets_nd2_partitions.txt) for phylogenetic analysis.

#### File: phylogenies.zip

**Description:** This folder contains two files in Newick format: 1) the IQ-TREE analysis of the mtDNA ND2 data (nd2-iqtree.tree); 2) the neighbor-joining tree created from the concatenated alignment of DArTseq data (concat_nj.tree).

#### File: R\_data.zip

**Descripti...