Proportion of identified relevant studies on genetics in amphibians, birds, carnivores, molluscs and rodents published in 2017–2018. Lethal and invasive methods of DNA collection are in red tones, non-invasive in blue tones, grey symbolizes that both invasive and non-invasive methods were used for DNA collection. Except for studies on carnivores, majority of studies used a lethal or an invasive genetic sampling technique.