Metta Muralidhar, Schlötterer Christian
Institut für Populationsgenetik, Veterinärmedizinische Universität Wien, Wien, Austria.
BMC Evol Biol. 2008 Jun 24;8:182. doi: 10.1186/1471-2148-8-182.
The origin of functional innovation is among the key questions in biology. Recently, it has been shown that new genes could arise from non-coding DNA and that such novel genes are often involved in male reproduction.
With the aim of identifying novel genes, we used the technique "generation of longer cDNA fragments from serial analysis of gene expression (SAGE) tags for gene identification (GLGI)" to extend 84 sex-biased 3'end SAGE tags that previously could not be mapped to the D. pseudoobscura transcriptome. Eleven male-biased and 33 female-biased GLGI fragments were obtained, of which 5 male-biased and 3 female-biased tags corresponded to putatively novel genes. This excess of novel genes with a male-biased gene expression pattern is consistent with previous results, which found novel genes to be primarily expressed in male reproductive tissues. 5' RACE analysis indicated that these novel transcripts are very short in length and could contain introns. Interspecies comparisons revealed that most novel transcripts show evidence for purifying selection.
Overall, our data indicate that among sex-biased genes a considerable number of novel genes (approximately 2-4%) exist in D. pseudoobscura, which could not be predicted based on D. melanogaster gene models.
功能创新的起源是生物学中的关键问题之一。最近的研究表明，新基因可能起源于非编码DNA，并且这些新基因通常与雄性生殖有关。
为了鉴定新基因，我们使用了“从基因表达序列分析（SAGE）标签生成更长的cDNA片段以进行基因鉴定（GLGI）”技术，来扩展84个之前无法映射到拟暗果蝇转录组的性别偏向性3'端SAGE标签。我们获得了11个雄性偏向和33个雌性偏向的GLGI片段，其中5个雄性偏向和3个雌性偏向的标签对应于推测的新基因。这种具有雄性偏向性基因表达模式的新基因过量现象与之前的结果一致，之前的研究发现新基因主要在雄性生殖组织中表达。5' RACE分析表明，这些新转录本长度非常短，并且可能包含内含子。种间比较显示，大多数新转录本表现出纯化选择的证据。
总体而言，我们的数据表明，在拟暗果蝇的性别偏向性基因中，存在相当数量（约2 - 4%）的新基因，这些基因无法根据黑腹果蝇的基因模型进行预测。
