SULANDARI S, ZEINMS A. 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. . HAYATI J Biosci [Internet]. 1 [cited 2024May4];19(4):183. Available from: https://journal.ipb.ac.id/index.php/hayati/article/view/%20%3Cp%20class%3D%22MsoNormal%22%20style%3D%22margin-bottom%3A.0001pt%3Btext-align%3Ajustify%3Btext-indent%3A14.15pt%3Bline-height%3Anormal%3B%22%3E%3Cspan%20style%3D%22font-size%3A9pt%3B%22%3EVisually%20identifying%20the%20sex%20of%20a%20bird%20can%20be%20difficult.%20It%20cannot%20be%20done%20in%20half%20the%20world%E2%80%99s%20species%20when%20they%20are%20adults%2C%20and%20virtually%20none%20can%20be%20sexed%20as%20chicks.%20Despite%20this%2C%20the%20sex%20of%20a%20bird%20is%20vital%20for%20captive%20breeding.%20An%20increased%20number%20of%20birds%20are%20being%20sexed%20using%20DNA%20amplification%20techniques.%20In%20this%20approach%2C%20the%20CHD-W%20and%20CHD-Z%20are%20distinguished%20by%20the%20amplification%20of%20an%20intron%20present%20in%20both%20genes.%20PCR%20products%20on%20the%20gel%20electrophoresis%20vary%20in%20size%20revealing%20one%20band%20in%20males%20at%20the%20CHD-Z%2C%20and%20two%20bands%20in%20females%20corresponding%20to%20both%20the%20CHD-W%20and%20CHD-Z.%20Two%20independent%20sets%20of%20primer%20%28P8%2FP2%20and%202550F%2F2718R%29%20were%20used%20to%20amplify%20the%20CHD%20gene%20region%20from%20both%20the%20Z%20and%20W%20chromosome.%20One%20hundred%20and%20ten%20%28110%29%20birds%20were%20sexed%20using%20first%20pair%20of%20primers%3A%20%28P8%2FP2%29.%20Sexing%20results%20indicated%20that%2081.8%25%20were%20successfully%20determined%2C%2012.7%25%20failed%20to%20be%20amplified%20and%205.5%25%3Cspan%3E%C2%A0%20%3C%2Fspan%3Ewere%20not%20perfectly%20determined%20because%20the%20PCR%20products%20showed%20thick%20band.%20The%20thick%20band%20caused%20misidentified%20female%20to%20male%20birds.%20An%20alternative%20primer%20%282550F%2F2718R%29%20was%20applied%20to%20solve%20the%20problem.%20Two%20hundreds%20and%20twenty-nine%20birds%20were%20sexed%20and%20the%20results%20showed%20100%25%20successfully%20determined.%20From%20this%20study%2C%20it%20is%20suggested%20to%20use%20a%20pair%20of%202550F%20and%202718R%20primers%20for%20distinguishing%20a%20male%20from%20a%20female%20bird.%3C%2Fspan%3E%3C%2Fp%3E%20