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

Abstract

Visually identifying the sex of a bird can be difficult. It cannot be done in half the world's species when they are adults, and virtually none can be sexed as chicks. Despite this, the sex of a bird is vital for captive breeding. An increased number of birds are being sexed using DNA amplification techniques. In this approach, the CHD-W and CHD-Z are distinguished by the amplification of an intron present in both genes. PCR products on the gel electrophoresis vary in size revealing one band in males at the CHD-Z, and two bands in females corresponding to both the CHD-W and CHD-Z. Two independent sets of primer (P8/P2 and 2550F/2718R) were used to amplify the CHD gene region from both the Z and W chromosome. One hundred and ten (110) birds were sexed using first pair of primers: (P8/P2). Sexing results indicated that 81.8% were successfully determined, 12.7% failed to be amplified and 5.5% were not perfectly determined because the PCR products showed thick band. The thick band caused misidentified female to male birds. An alternative primer (2550F/2718R) was applied to solve the problem. Two hundreds and twenty-nine birds were sexed and the results showed 100% successfully determined. From this study, it is suggested to use a pair of 2550F and 2718R primers for distinguishing a male from a female bird.

Molecular techniques for sex identification of captive birds

“…Bird sex can be ascertained from the CHD-W gene using the Po primer and multiplex PCR methods [16], and real-time PCR [14]. Sex identification of birds for breeding purposes may use the P8/P2 primer on the CHD gene for the two sex chromosomes, W and Z [17]. Three primers: HD1F/CHD1R, 2550F/2718R, and P2/P8 are used to determine the sex of birds [18]; PCR methods are more accurate than morphometry and DNA finger-printing for sex identification in birds [19].…”

Identification of Y chromosome markers in the eastern three-lined skink (Bassiana duperreyi) using in silico whole genome subtraction

“…That said, the amplified sex specific region revealed some divergence between the Anglesea population and the Piccadilly Circus populations, suggesting that mutations could occur in the primer sites of some populations/taxa, limiting the generality of the sex- linked markers. The identification of sex-specific sequence has important practical value in many contexts, including ecological studies [63][64][65], conservation of threatened or endangered species [66][67][68][69], captive breeding [70], aquaculture [71,72], elimination of mortality as a possible explanation for sex ratio bias [32,73] sex forensics [74] and identifying genotypic sex [32,75,76] or in studies of early developmental processes where sex of the developing embryo is important [77,78]. Two approaches for identifying sex linked markers using whole genome sequencing seem appropriate, both relying on the divergence of the X and Y homologues in the region of recombination suppression.…”

Sex identification in embryos and adults of Darwin’s finches

“…Different primer sets based on the CHD1 gene have been used to sex birds [26,28–30]. We chose two that have been successful in many passerines [27] and introduced minor modifications to their sequences.…”

“…CHD1 is a highly conserved gene, which makes it a candidate for universal non-ratite avian sex identification. A number of studies have reported specific PCR primers to screen the intron variants of the Z and W alleles and have successfully applied these to many avian species [26–30]. The difference between the size of the male and female fragments vary between species and primer pairs.…”