By Isabel Ovalle
The Genomics Core Laboratory at Weill Cornell Medical College (WCMC) in Qatar has decoded the Genome Sequence of the Arabian Oryx. The results of this work were published in the summer of 2012. Six months have passed and researchers are now preparing to take up a new challenge with the New Year: Collecting more samples and sequencing the genomes of at least 50 more oryx.
Joel A Malek, PhD, Assistant Professor in Genetic Medicine and Director of the Genomics Core Laboratory at WCMC in Qatar, leads the team that first sequenced the genome of the oryx from a DNA sample provided by a male in the Wabra Wildlife Preservation in Qatar.
Back in 2011 the Ministry of Environment decided to develop a project to sequence the oryx genome with the knowledge that it was in danger of extinction. Currently the population of this species is about 10,000. However, studies developed at the Genomics Core Laboratory have concluded that the genome of this species is very homogeneous because of inbreeding.
“At the moment the population of oryx is about 7,000 to 10,000, but the DNA left is only that of the original population. Even though they have offspring, the DNA is really that of only four or five animals,” explained Malek.
The task of first sequencing a genome is difficult because there is no guide to it and the genome has about eight million letters. The professor stated: “We take millions of these and read the sequence on the machine, which produces a text file. We have to put them back together using a really big computer and this takes a long time.”
Nevertheless, now that WCMC researchers have the first genome, sequencing another one will be much easier. “The puzzle has been solved and we can use that information to help with the new one,” said Dr Malek.
All animals have 23 strands of DNA in every cell of their body, half of those chromosomes come from the mother and the other half from the father. When a genome is decoded scientist find two copies of each. In the case of the Arabian Oryx, very few differences were found between the mother and the father’s DNA, “that means the mother and the father are probably very related, given that normal sibling’ DNAs are not so similar”, clarified Malek.
Sadly, this finding is relevant because it’s a bad sign. In the first genome the amount of variation between the mother and the father was about three times less than in most normal organisms which have about three to four million differences, while the Oryx from Wabra Wildlife Preservation in Qatar only had less than a one million variations.
This finding reveals it’s a multiple generation problem and establishes the next step to take, which is none other than understanding what the situation is in the entire world of oryx. To achieve this goal, researchers need to sequence about 50 more genomes which will be taken not only from Qatar, but also from neighbouring countries as well as the UK and the US. This work will hopefully clear out what the true situation is.
To help comprehend the situation of oryxs, Malek talked about the Panda. Currently there are around 2,000 Pandas in the world. The sequence of one of these animals was also sequenced, and at least three million differences were found between the mother and the fathers DNA.
The conclusion is that, “even though the Panda is endangered by numbers, genetically it’s not that endangered. My theory is that the oryx and the Panda became endangered in very different ways,” added Dr Malek.
If the new phase of the study performed by WCMC concludes that there is few variations among other herds of oryx, the recommendation to breeders will be to implement better reproduction programmes.
“Genetic variation allows animals to respond better to environment change, it’s almost like a weapon a population has for surviving whenever there’s water, disease or food change. If you have a lot of variation you are much more capable to adapting to that change. If you have no variation, and you get the wrong disease, everybody will die,” warned this researcher.
The genomics core lab hopes to finish the new research within six months from now. However, Dr Malek has doubts that every flock will present the same genetic homogeneity. “What I suspect is that the population is pretty inbred, probably in the Emirates or Saudi Arabia the situation is the same, but maybe a private collection in Oman will have a population that is a bit different from the others. At that point, we would recommend that that group in Oman is bred with the others.”
The amount of variation found in the Arabian Oryx is probably the lowest found in a genome that is not known to be inbred. Even though genetic diversity is not a guarantee of goodness, experts say that variation usually means that there are less genetic disorders and that the population is more capable of adapting to the environment.
Lack of genetic differences can impact in different ways, for instance in the ability these animals have to detect rain from a distance of 40km. “It’s possible that some animals with no variation in their DNA can’t sense the rain,” added Malek, “by having variations they can adapt, if you are genetically one type, you only have one option”.
The Peninsula
About oryx, published
