Detection of Illegal trade in the Cape Parrot and Blue Crane using DNA

Tiawanna Taylor

Both the Blue Crane and Cape Parrot suffer from illegal trade in South Africa where chicks, or eggs, are removed from the nests of wild breeding pairs. Both these species are protected by South African legislation and permits are required by anyone wanting to possess, own or trade these birds. In order to obtain a permit, birds should be captive bred. However, illegal traders often operate by fraudulently obtaining permits, by falsely claiming that they have captive bred the chicks themselves. Proving that this is not the case, in order to prosecute offenders, can be difficult.

A potential method that can assist the authorities is DNA technology. DNA profiling can, and has, been used to detect illegal trade of wildlife, providing investigating authorities with evidence that can be used in court to assist the prosecution of offences.

How does it work?

Very basically the DNA, examined in this type of investigation, is made up of two complimentary strands. One of these strands is inherited from an individual's mother, the other strand from its father. Therefore, an individual inherits 50% of its genetic make up from its mother and 50% from its father. This enables us to trace the DNA of an individual back to each of its parents. In addition, because the DNA of every individual is unique (except in the case of identical twins) it is also possible to identify any specific individual and therefore for example tie a scene of crime sample to an individual.

Human DNA Profiling history
 

Human DNA profiling, to detect crime, has been around since the 1980's. The first occasion that it was officially used as forensic evidence was in 1986. A suspect, who had pleaded guilty to a rape and murder, was shown to be not guilty of the offence - his DNA did not match the semen samples obtained from the scene of the crime. DNA fingerprinting was subsequently used to identify the true killer, who was found following mass DNA sampling of the local male population. Since this time, the technology and techniques available to investigators have advance tremendously. So much so that in human forensics DNA can be extracted from tiny trace samples, as small for example as from the saliva used to lick the back of a stamp that was used to send a postal bomb.

Wildlife DNA Profiling

The main difference for wildlife DNA forensics is that whereas the genetic markers required to create profiles are readily available for humans, this is not generally the case for wildlife. Some methods require a unique sets of genetic markers to be developed for each new species, all require additional validation to be undertaken and the development of reference sets. This can be both time consuming and costly.

However, once genetic markers are developed the DNA techniques used for wildlife investigations are similar to those used in human DNA investigations that have recently become very popular on TV. For example the identification of individuals involved in crimes e.g. rape or burglaries where DNA evidence can be collected. When applied to wildlife, identification of individuals can be helpful where an animal has been stolen from its owner.

Similarly, in humans, determining the parentage of an individual can be used to check paternity, or identifying bodies following mass catastrophes such as the tsunami. The same techniques can be used with wildlife, such as in this research, to detect illegal trade in chicks and eggs stolen from the wild, a common forensic use would be to prove that an individual is not the offspring of the captive pair claimed to be its parents.

Microsatellite Genetic Markers for the Cape Parrot and Blue Crane

As part of a collaborative project between the University of KwaZulu-Natal in South Africa and the University of Sheffield (UK) a set of genetic markers have been developed for both the Blue Crane and Cape Parrot. Two South African MSc students have spent a total of 1 year based at the Sheffield molecular laboratory learning some of the specialist techniques required to develop this type of genetic marker. The genetic markers, known as 'microsatellites', have now been developed. They are currently being analysed before being made available for forensic use in detecting illegal trade in these species.

Microsatellite genetic markers detect sections of the DNA that are repeated in tandem, e.g. GGATGGATGGATGGAT would represent the sequence GGAT repeated 4 times. These markers are ideal for detecting parentage and relationships. Firstly due to a number of factors these repeat regions are highly variable within a population or species, and the number of repeats can be scored, enabling the identification of unique profiles. However, at the same time an individual will inherit the repeat type of its parents, which enables an individual's profile to be matched to its parents. Combining the profiles of a number of these markers can provide the high statistical powers of discrimination required for legal investigations. (For an example, see here).

Other Conservation Applications

Although the main aim of their development was to provide forensic markers these genetic markers also have wider conservation applications. In wild populations they could potentially be used to answer questions relating to the genetic diversity of different populations, to determine the degree of dispersal and exchange of individuals between the populations and to assist their conservation.

These markers can also be used to assist management of captive populations, providing another important tool to conservationists or breeders. As with wild populations the genetic diversity can be examined and levels of inbreeding determined either within a breeding establishment or groups of birds maintained through a studbook. In addition the amount of genetic similarity or relatedness between individuals can be useful in selecting appropriate breeding pairs to reduce potential for inbreeding, necessary in sustaining viable breeding populations.

Other Forensic Wildlife in South Africa

There is an increasing interest in wildlife forensics in South Africa. With a number of initiatives taking place around the country. Methods to detect illegal trading are available or being developed for a number of species including: cycads, abalone, antelopes, cheetah.

In addition to DNA markers there are many other techniques, spanning a vast range of technology, that have a part to play in detecting wildlife crimes. These again have mainly began as techniques to investigate human crime and include: document, digital and electronic data analysis; analytical chemistry; stable isotope analysis; mass spectrometry, poisons and pathology analysis.

Training in using DNA as evidence for Wildlife Officers

The development of the genetic markers is just one aspect that this project focuses upon. A set of guidelines and workshops are also being developed with the aim of provide assistance to wildlife investigators who may wish to use DNA evidence to detect and prosecute wildlife crime.

 

October 2006