Evolutionary patterns in Sylvia curruca complex species

Determining the limits of species is still a major area of contention, particularly when diagnostic differentiating characters are subtle and there is a contradiction between morphological and genetic data. The Lesser Whitethroat (LWT) complex Curruca curruca represents an interesting study system to address this issue. Here, we use phylogeny-, admixture- and principal component analysis- (PCA-) based analyses on whole-genome sequence data of the parapatric LWT taxa C. c. curruca, C. c. halimodendri, C. c. zagrossiensis and C. c. althaea to investigate the prevalence and importance of gene flow in a geographical area where morphological evidence suggests a clinal transition between populations. The results suggest that LWT populations of the Zagros Mts zagrossiensis may represent a lineage historically diverged from topotypical curruca, the two lineages later coming into secondary contact with extensive gene flow as a result. There is no evidence of a hybrid zone or cline between zagros..., - Blood and samples were obtained from wild birds in nature.
- Sequencing library preparation for the genomic DNA using 150bp paired-end sequencing was carried out according to the TruSeq DNA PCR-free protocol and the sequencing was performed on the Illumina HiSeq2500 platform at NGI Stockholm. ,

物种边界的划定仍是学界颇具争议的核心议题之一，尤其是当物种间的诊断性鉴别特征细微难辨，且形态学数据与遗传学数据存在冲突时。白喉林莺（Lesser Whitethroat, LWT）复合群*Curruca curruca*便是解决这一科学问题的理想研究体系。本研究针对邻域分布的白喉林莺类群*C. c. curruca*、*C. c. halimodendri*、*C. c. zagrossiensis*以及*C. c. althaea*的全基因组测序数据，开展基于系统发育分析、群体混合分析以及主成分分析（Principal Component Analysis, PCA）的综合研究，以探究在形态学证据显示种群间存在渐变过渡的地理区域内，基因流的普遍程度与演化重要性。
研究结果表明，扎格罗斯山脉的*zagrossiensis*种群可能是一个与指名*curruca*类群在历史上发生分化的演化支系，二者后续再次接触并由此产生了广泛的基因交流。尚未发现*zagros*类群与其他类群间存在杂交带或渐变群的证据。——本研究的血液与样本均采自野外野生鸟类。
本研究采用150bp双端测序策略，参照TruSeq DNA PCR-free建库试剂盒流程完成基因组DNA文库构建，并于瑞典国家基因组中心（National Genomics Infrastructure, NGI）斯德哥尔摩分部的Illumina HiSeq2500测序平台完成测序。