DNA sampling from eggshells and microsatellite genotyping in rare tropical birds: Case study on Brazilian Merganser

Abstract

This study shows that sampling maternal DNA from hatched and abandoned eggshells is a viable noninvasive strategy for studying the genetics of rare or endangered tropical birds, as exemplified here by the Brazilian Merganser (Mergus octosetaceus). Eighteen microsatellites were isolated from enriched libraries and nine heterologous loci from related species were tested. Seven loci were amplified successfully, with five of them being polymorphic. These loci exhibited amplicons ranging from 110 to 254 bp for 132 samples, with 60 from eggshells and 72 from blood or muscle samples. The number of alleles for M. octosetaceus ranged from one to six (mean = 3.71), which is low compared to M. merganser (1-15 alleles), a ‘least concern’ species. Genetic diversity did not differ significantly between noninvasive and invasive samples (Z(u) = 0.31, p = 0.37). Thus, noninvasive sampling, as demonstrated here with eggshells, provides an efficient means to assess genetic diversity in tropical birds without the need to capture and handle them.

Population genomics of the critically endangered Brazilian merganser

“…3) and DAPC (Fig. 4), corroborating previous genetic studies with mitochondrial and microsatellite markers 22,24 , which found greater similarity between PSC and APR populations when compared with PCV.…”

“…Intensive eld studies have been done since the 1990's in the Serra da Canastra National Park, located in southeastern Brazil, where the largest population of the species has been recorded so far 13,14,18,19 . Furthermore, only four genetic studies of the Brazilian merganser were published so far by our research group 21,22,23,24 , showing preliminary data that indicate a low genetic diversity likely related to a recent bottleneck in the remaining populations. However, no genomic data has been used so far with conservation purposes for the remaining populations of Brazilian merganser.…”

Towards more compassionate wildlife research through the 3Rs principles: moving from invasive to non-invasive methods

“…In birds, eggshells (Strausberger and Ashley 2001, Egloff et al 2009, Kjelland and Kraemer 2012, Maia et al 2017 or feathers (Rudnick et al 2007, Kjelland and Kraemer 2012, Olah et al 2016) can be used as a source of DNA. Feathers can be collected opportunistically or through a feather-trap (Maurer et al 2010).…”

Current trends in the application of non-invasive genetic sampling to study Neotropical birds: Uses, goals, and conservation potential

“…53,54 Eggs were used as source of DNA for the molecular identification of three Neotropical parrot and one owl species victims of illegal traffic, 37 and to assess the genetic diversity of the critically endangered Brazilian Merganser ( Mergus octosetaceus ). 40 Bird carcasses were used as source of DNA for molecular identification of the species involved in collisions with terrestrial vehicles. 49,50 In cases such as these, when the physical deterioration of the remains preclude a reliable morphological identification of the species killed, the molecular identification is usually the only alternative.…”