Blood, sweat and tears: non-invasive vs. non-disruptive DNA sampling for experimental biology

Abstract

may be necessary to obtain DNA from an organism before using it in a bioassay or an experiment, to identify and distinguish between cryptic species, or when comparing different morphocryptic genotypes. Another example could be the assessment of relatedness between organisms prior to a behavioural study. In such cases, DNA must be obtained without affecting the fitness or behaviour of the subject being tested, as this could bias the results of the experiment. This points out the existence of a gap in the current molecular and experimental biology terminology, for which we propose the use of the term non-disruptive DNA sampling, specifically addressing behaviour and/or fitness, rather than simply physical integrity (invasiveness). We refer to these methods as "nondisruptive", and discuss when they are appropriate to use. it may be necessary to obtain DNA from an organism before using it in a bioassay or 42 an experiment, to identify and distinguish between cryptic species, or when 43 comparing different morphocryptic genotypes. Another example could be the 44 assessment of relatedness between organisms prior to a behavioural study. In such 45 cases, DNA must be obtained without affecting the fitness or behaviour of the subject 46 being tested, as this could bias the results of the experiment. This points out the 47

An environmental DNA‐based method for monitoring spawning activity: a case study, using the endangered Macquarie perch (Macquaria australasica)

“…For aquatic vertebrates relying on external fertilizations (e.g. most fishes and frogs) monitoring reproductive activity can be achieved by destructive, injurious or non-invasive methods (Table 1) (Lefort et al 2015). The extra mortality rate imposed by destructive sampling methods makes them undesirable for monitoring reproduction in rare and threatened species (Tsukamoto 2006;Wei et al 2009;Engstedt, Engkvist & Larsson 2014).…”

“…Non-exhaustive list of categories for monitoring methods that can be used to monitor reproductive activity in aquatic vertebrates relying on external fertilization. Definitions for the different categories were modified fromLefort et al (2015) …”

Development of an easy and cost-effective method for non-invasive genotyping of insects

“…Non-lethal techniques have been developed to extract insect DNA from frass (feces) and exuviae (shed exoskeleton) [8,9]. This approach is particularly useful for insects at the larval stage of development, where large quantities of frass are generated, or when instars shed their exoskeletons [10,11].…”

“…This approach is particularly useful for insects at the larval stage of development, where large quantities of frass are generated, or when instars shed their exoskeletons [10,11]. Before using an organism in a bioassay to distinguish between cryptic species, to differentiate cryptic morphs, or assess relatedness between organisms before a behavioral study, DNA must be obtained without affecting the fitness or behavior of the organism [8]. However, the detection rate is not high with these methods due to degradation of DNA by nucleases in frass or exuviae samples collected in the field [12].…”

Identifying a breeding habitat of a critically endangered fish, Acheilognathus typus, in a natural river in Japan

“…Compared to disruptive survey methods, such as gill netting or the usage of toxins, eDNA methods are less disruptive for the target species and ecosystems and can be used to survey the distribution of rare species (Jerde et al 2011;Lefort et al 2015). Recent studies have shown that eDNA analysis can be applied for specifying the breeding season or spawning activity by monitoring the change in eDNA concentration or ratio of nuclear to mitochondrial eDNA markers (Spear et al 2014;Erickson et al 2016;Buxton et al 2017;Bylemans et al 2017).…”