For the first time a whole genome analysis has been conducted for the Atlantic puffin. The results are important in order to conserve the genetical variation.
Since the middle of the last century,the number of seabirds has declined by 70 percent worldwide. Røst in Lofoten still has one of the world’s biggest colonies of Atlantic puffins (Fratercula arctica). Although nine of the past thirteen breeding seasons have resulted in very few offspring. Globally,puffinsare classified as vulnerable toextinction,andpastbreeding seasons have made researchers very concerned.Puffins live for a very long time. Thus it takes time before breeding problemstranslate to declines inpopulation size. What happens is that the chicks die before they are ready to leave the nest. The adult population is fairly stable, but when few chickens survive there will be trouble in the long run.
In light of thedramatical decline in the number ofseabirds,itisparticularilyimportantto conserve thepresentgenetic variation.Previously,it has been assumed that puffins can be divided into three subgroups according to geographical distribution and size. It has also been assumed that the genetical variation is evenly distributed among the different colonies. This assumptionwas based on analyses of smaller parts of thegeneticmaterial.Yet,Sanne Boessenkool andOliver Kerstenat CEES wanted to investigate if this assumption was true.
“When you want to conserve a species, you want to conserve the geneticvariation. In order to dosoonemust know whatand where thevariation is,andwhat you lose, if you lose a population,” explains Boessenkool.
Seabirds have the possibility to fly over great distances. Nevertheless,manybreed at the same place every year, some with the same mate for life.
Therefore, it is important to know if thegenetic diversityisevenly spread out amongst all puffins, or if different colonies become more genetically different over time.
Several surveillance programmes (SEAPOP, SEATRACK, ARCTOX) have contributed with sample collection and interpretation of the results. Researchers on these programmes know the ecology and the species very well. The local partners have collected the blood samples and feathers at the same time as they carried out surveillance andringingofbirds atthevariouspopulations. Without the international cooperation the researchwould havebeen very complicated.Halfof the year,the puffins are at the open sea. To collect samples fromvarious locations within the breeding season it was necessary to cooperate with several partners.
As a result, Boessenkool and Kersten sequenced thegeneticmaterial of 72 individuals from 12 different colonies.
Previously,puffins were divided into three subgroups, though some researchers claimed that there were only two. These groups were largely based on size and geographical distribution, with the largest subgroup in the north and the smallest ones in the south.
“The genetical studies show that there are at least four subgroups or groups of colonies,” explains Kersten.
One of the subgroupsarethe largest puffins, which only exist in theArctic part of the world. One of the other groups is locatedonthe west coast of Canada and the US.
Most of previousgenetic analyses of seabirdshadbeen done on thegeneticmaterial from mitochondria, or certain parts of the genome. Thesehad oftennot showngeneticdifferences between the populations and colonies.Yet, the new study shows that the mitochondrial DNA is not a goodstarting pointto look for genetic variation and differences in today’s seabirds.Nevertheless, conductingwholegenome analyses is expensive and time consuming, a reason whyit hasn’t been applied very often previously.
When the researchers in this study looked at the whole genomeof the puffinthey were able to identify substantialdifferences between the populations.
Methodscouldbe improved in the long run
This study shows the importance of doingwholegenome sequencing torevealthe distribution ofgenetic diversity. Kersten and Boessenkools findingscould alsohave consequences for future methods.
The researchers are trying to identify some areas in the genome where the differences between the groups of puffins are mostpronounced. This means that future research projects or surveillance projects without the funds toconduct a wholegenome analysis can concentrate oncertainareasin the genomethat will function as markers. This is not possible today, but the researchers are hoping tocreatea database with such markers.
We need to take better care of local puffin colonies
When the variation betweengroups ofcolonies is sopronounced,each group and sometimesevery local colony is importanttoconservethegenetic diversityof the whole species. Previously it was assumed that if a group of puffinswasdoing poorly the genetic variation was still conserved in other colonies or groups, butthat is likely not true. To conserve the species,every colony is important. Exactly how to turn around the recent development for seabirds is not clear to the scientists, but just to be aware of the significance of each colony may be important.
Different groups of puffins may be adapted to different environments. With climate change it is important that we conserve as much of the diversity as possible, because some groups can be better adapted to these changes than others, but we do not necessarily know which.
IMAGE CREDIT: Elina Melteig