食肉目犬型超科(Caniformia)各科间的系统发育关系一直是近年来食肉目系统发育关系研究的热点，至今仍处于众说纷纭的状态，尤其是小熊猫科的系统发育位置。小熊猫因其似熊非熊的形态特征，使得它的进化地位存在很大的争议，无法得到解决。
中国科学院昆明动物研究所张亚平院士、云南大学于黎研究员和博士研究生栾鹏涛结合模式生物基因组信息，系统筛选获得了22个新的单拷贝核基因内含子片段，将它们用于食肉目科间系统发育关系研究。研究结果支持小熊猫是浣熊科和鼬科的姐妹群，不支持形态学研究将小熊猫归于浣熊科，或将大，小熊猫并为熊猫科的观点，也不支持线粒体基因组研究中认为小熊猫与臭鼬科或由浣熊科，鼬科和臭鼬科组成的进化枝关系最近。
该研究不仅提供了重要的系统发育信息，还在新筛选的核基因内含子中报道了大数量的等位基因杂合子(Intra-individual Allele Heterozygotes) 现象。
这项研究提供了一个使用大规模内含子数据进行哺乳动物分子系统学研究的成功范例，而且为脊椎动物分子系统学研究提供了新的核基因标记。
该研究文章发表在Systematic Biology上。（生物谷Bioon.com）
生物谷推荐原文出处：
Syst Biol (2011) 60 (2): 175-187. doi: 10.1093/sysbio/syq090
Phylogenetic Utility of Nuclear Introns in Interfamilial Relationships of Caniformia (Order Carnivora)
Li Yu1,2,*?, Peng-Tao Luan1,2,?, Wei Jin1,2, Oliver A. Ryder3, Leona G. Chemnick3, Heidi A. Davis3 and Ya-ping Zhang2,*
Abstract
The monophyletic group Caniformia (dog-like carnivores) in the order Carnivora comprises 9 families. Except for the general consensus for the earliest divergence of Canidae and the grouping of Procyonidae and Mustelidae, conflicting phylogenetic hypotheses exist for the other caniformian families. In the present study, a data set comprising > 22 kb of 22 nuclear intron loci from 16 caniformian species is used to investigate the phylogenetic utility of nuclear introns in resolving the interfamilial relationships of Caniformia. Our phylogenetic analyses support Ailuridae as the sister taxon to a clade containing Procyonidae and Mustelidae, with Mephitinae being the sister taxon to all of them. The unresolved placements of Ursidae and Pinnipeds here emphasize a need to add more data and include more taxa to resolve this problem. The present study not only resolves some of the ambiguous relationships in Caniformia phylogeny but also shows that the noncoding nuclear markers can offer powerful complementary data for estimating the species tree. None of the newly developed introns here have previously been used for phylogeny reconstruction, thus increasing the spectrum of molecular markers available to mammalian systematics. Interestingly, all the newly developed intron data partitions exhibit intraindividual allele heterozygotes (IIAHs). There are 115 cases of IIAHs in total. The incorporation of IIAHs into phylogenetic analysis not only provides insights into the interfamilial relationships of Caniformia but also identifies two potential hybridization events occurred within Ursidae and Otariidae, respectively. Finally, the powers and pitfalls of phylogenetics using nuclear introns as markers are discussed in the context of Caniformia phylogeny.
