Comparison of different procedures of DNA analysis for sex identification in the endangered bearded vulture (Gypaetus barbatus)

Abstract

During the last century, bearded vulture populations have declined and are threatened by extinction in Europe. Conservation efforts such as captive-bird breeding programs require the knowledge of the sex of individuals. The bearded vulture is difficult to sex morphologically because it is sexually monomorphic. Until now, there were no published genetic methods to sex this species. In our study, we tested different methods based on polymerase chain reaction analysis of the chromobox-helicase-DNA binding protein gene. This gene is located on both sex chromosomes, but the two copies differ in size depending on chromosomal location. Differences can be detected by digestion with restriction enzymes or with the amplification refractory mutation system technique. These methods are quick, accurate, and inexpensive and allow a large scale sex typing of bearded vultures.

Application of Two Molecular Sexing Methods for Indonesian Bird Species: Implication for Captive Breeding Programs in Indonesia

“…Sex identification of birds can provide researchers with important information regarding the ecology and behavior of bird species (Helander et al 2007), also provides valuable insights into their breeding strategies, conservation and management programs (Helander et al 2007;Garcia et al 2009;Naim et al 2011), reproduction programs of threatened species (Ellegren & Sheldon 1997). In birds, the absence of juvenile sexual dimorphism often makes it difficult or even impossible to determine a chick's sex on the basis of external morphology.…”

Short Communication Non-invasive sex identification of the white-bellied sea eagle (Haliaeetus leucogaster) through genetic analysis of feathers

“…Therefore, due to the ability of polyacrylamide gels, as opposed to agarose gels, to provide better resolution, their use is recommended for separation of the Z-and W-bands (Dubiec and Zagalska-Neubauer, 2006). Likewise, the length difference in P2/P8-amplified Z-and W-fragments, which are extremely short, making it hard to resolve them on agarose gels (Chang et al, 2008), was also reported in other raptors (Fridolfsson and Ellegren, 1999) and specifically in Accipitridae species (Sacchi et al, 2004;García et al, 2009). Moreover, gender assignment based on P2/P8 primers is difficult because of a polymorphism in the Z-chromosome, which has been documented in nearly 20 species of birds (see Dubiec and Zagalska-Neubauer, 2006 and reference therein).…”

“…Sex determination can provide researchers with important information regarding the ecology and behavior of bird species (Helander et al, 2007), and also provides valuable insights into their breeding strategies, conservation and management programs (Helander et al, 2007;García et al, 2009;Naim et al, 2011a). Adults of many avian species, particularly raptor, exhibit sexual size dimorphism even at the nestling or subadult stages (Millar et al, 1997;Helander et al, 2007), enabling sex determination based on morphometry (Helander et al, 2007).…”

Molecular Sex Determination of Captive Komodo Dragons (Varanus komodoensis) at Gembira Loka Zoo, Surabaya Zoo, and Ragunan Zoo, Indonesia

“…Sex identification provides valuable insights into species breeding strategies, which informs conservation and management programs (Helander et al 2007;Garcia et al 2009;Naim et al 2011) and reproduction programs for threatened species (Ellegren & Sheldon 1997). The most basic and important information in establishing captive breeding programs is a clear understanding of sex ratio; that is, the number of males and females in a population.…”