Bird sex-typing using genetic markers


The team in Sheffield has identified markers for the genetic sexing of over 150 species of birds (Dawson 2005, Dawson et al. 2015Dawson et al. 2016) and supported multiple studies involving bird sex-typing (see our publications).

We have assessed the utility of published sex-typing markers (Dawson et al. 2016)  and created a web-based database (see below) of the most suitable methods to sex-type different species.

We have also developed new sex-typing markers:

  • Marker Z37B is suitable for sex-typing birds from degraded samples and samples of low quantity (Dawson et al. 2015)
  • Marker Z43B is able to sex species that have been problematic to sex with other markers (Dawson et al. 2016).


We have assessed the utility of two commonly used published sex-typing markers (Griffiths et al. (1998: P2/P8) and Fridolfsson and Ellegren (1999: 2550F/2718R)).

In addition to the species we have sex-typed here at Sheffield, data was very kindly contributed from many researchers - we added all this data, along with the published original data, to the database.

The Bird sexing database Dawson, 2005 (MS Excel, 124kB) includes a list of ~130 bird species (non-passerines and passerines) which have been sexed and the sexing primer sets which were used. The database and details of the technical methods and protocols used are provided in this document (Word, 32kB).


Potential sources of error when sex-typing birds

We would also like to draw attention to the potential sources of error in misinterpreting molecular sexing data caused by the presence of Z allele polymorphism, such as that identified in auklets (Dawson et al. 2001) and other species (Dawson et al. 2015)


Dawson DA, Darby S, Hunter FM, Krupa AP, Jones IL and Burke T (2001) A critique of CHD-based molecular sexing protocols illustrated by a Z-chromosome polymorphism detected in auklets (Aves: Alcidae, Laridae). Molecular Ecology Notes, 1, 201–204.

Dawson DA, Brekke P, dos Remedios N, Horsburgh GJ (2015) A marker suitable for sex-typing birds from degraded samples. Conservation Genetics Resources,  7, 337–343 [Open Access].

Dawson DA, dos Remedios N, Horsburgh GJ (2016) A new marker based on the avian spindlin gene that is able to sex most birds, including species problematic to sex with CHD markers. Zoo Biology, 35, 533–545. [Open Access]

Bruford MW, Hanotte O, Brookfield JFY, Burke T (1998) Multilocus and single-locus DNA fingerprinting. In: Molecular Genetic Analysis of Populations: A Practical Approach, 2nd edition, (ed. Hoelzel AR), pp. 287-336. IRL Press, Oxford.

Dawson DA (2005) NBAF-S Bird sexing database: Identifying suitable sex-typing markers for over 100 bird species.

Fridolfsson AK and Ellegren H (1999) A simple and universal method for molecular sexing of non-ratite birds. Journal of Avian Biology, 30, 116-121.

Griffiths R, Double MC, Orr K and Dawson RJG (1998) A DNA test to sex most birds. Molecular Ecology, 7, 1071-1075.

The NERC Environmental Omics Facility (NEOF)

Making state-of-the-art molecular genetics facilities and training available to the UK science community.