ausblenden:
Schlagwörter:
Migration; Microarray Birds; Gene expression; Behavior; Calcium transport; Synapse; Phylloscopus trochilus
Zusammenfassung:
Background: We still have limited knowledge about the underlying genetic mechanisms that enable migrating
species of birds to navigate the globe. Here we make an attempt to get insight into the genetic architecture
controlling this complex innate behaviour. We contrast the gene expression profiles of two closely related
songbird subspecies with divergent migratory phenotypes. In addition to comparing differences in migratory
strategy we include a temporal component and contrast patterns between breeding adults and autumn
migrating juvenile birds of both subspecies. The two willow warbler subspecies, Phylloscopus trochilus trochilus
and P. t. acredula, are remarkably similar both in phenotype and genotype and have a narrow contact zone
in central Scandinavia. Here we used a microarray gene chip representing 23,136 expressed sequence tags
(ESTs) from the zebra finch Taeniopygia guttata to identify mRNA level differences in willow warbler brain
tissue in relation to subspecies and season.
Results: Out of the 22,109 EST probe sets that remained after filtering poorly binding probes, we found 11,898
(51.8 %) probe sets that could be reliably and uniquely matched to a total of 6,758 orthologous zebra finch genes. The
two subspecies showed very similar levels of gene expression with less than 0.1 % of the probe sets being significantly
differentially expressed. In contrast, 3,045 (13.8 %) probe sets were found to be differently regulated between samples
collected from breeding adults and autumn migrating juvenile birds. The genes found to be differentially expressed
between seasons appeared to be enriched for functional roles in neuronal firing and neuronal synapse formation.
Conclusions: Our results show that only few genes are differentially expressed between the subspecies. This suggests
that the different migration strategies of the subspecies might be governed by few genes, or that the expression
patterns of those genes are time-structured or tissue-specific in ways, which our approach fails to uncover. Our
findings will be useful in the planning of new experiments designed to unravel the genes involved in the migratory
program of birds.
