2.1. Sampling and DNA extractions
Tails tissues of 100 specimens of Podarcis lilfordi were
collected between 2015 and 2016 from eight islets in the Menorca and
Mallorca archipelagos (Balearic Islands) (10-22 samples per islet)
(Figure 1 and Table 1). Islets encompassed a representative subsample of
the current species geographic distribution and vary in several
geographic and ecological aspects, including surface area, maximum
altitude, vegetation cover and type, presence of human settlements and
other vertebrates, as well as lizard demographic traits (Mayol et al.,
2020; Pérez-Mellado et al., 2008; Rotger et al., 2021). Specimens were
captured using pitfall traps placed along paths and vegetation edges,
sexed according to visual examination and morphology (Rotger et al.,
2016), weighted, and body size measured as snout to vent length (SVL)
(see Table S1 for specimen information). Tails were preserved in 100%
ethanol and kept at -80°C until processed. Permits for sampling were
provided by Conselleria d’Agricultura i Medi Ambient i Territori, Govern
de les Illes Balears (CEP 31/2015 to LB and CEP 6/14 to GT). Genomic DNA
was extracted with DNAeasy Tissue and Blood kit (Qiagen) with RNase
treatment. DNA concentration was measured with Qubit 2 fluorometer
(Invitrogen, Waltham). About 1 ug of genomic DNA per sample was sent toCentro Nacional de Analisis Genomico (CNAG, Spain) for
sequencing. DNA integrity and concentration was further measured on a
fragment analyzer (Agilent Bioanalyzer) and high-quality samples with at
least 10 ng/µl were selected for sequencing.