Jiang Y N, Wu C Y, Huang C Y, Chu H P, Ke M W, Kung M S, Li K Y, Wang C H, Li S H, Wang Y, Ju Y T
Department of Animal Science and Technology, National Taiwan University, Taipei, Taiwan.
J Anim Sci. 2008 Oct;86(10):2461-70. doi: 10.2527/jas.2007-0049. Epub 2008 Mar 14.
The Lanyu pig is an indigenous breed from the Lanyu Islet, which is southeast of Taiwan. Two herds of Lanyu pigs were introduced from the Lanyu Islet into Taiwan in 1975 and 1980. The current population of conserved Lanyu pigs consists of only 44 animals with unknown genetic lineage. The Lanyu pig possesses a distinct maternal genetic lineage remote from Asian and European pigs. The present study aimed to understand the phylogenetic relationship among conserved Lanyu, Asian, and European type pigs based on the cytochrome b coding gene, to ascertain the maternal lineage and genetic diversity within the conserved Lanyu pigs, and to address whether genetic introgression from exotic or Formosan wild pigs had occurred in the conserved Lanyu pigs. Entire mitochondrial genomes of both types of Lanyu pig comprised 2 ribosomal RNA, 22 transfer RNA, and 13 protein-coding genes. Only 2 haplotypes of the mitochondrial DNA (mtDNA) control region and cytochrome b were identified in the conserved Lanyu pig herds. When maximum likelihood trees were constructed, the Type I Lanyu mitochondrial genes formed a unique clade with a large pairwise distance of both cytochrome b and the control region from Asian and European type breeds, Formosan wild pigs, and exotic breeds. Significant loss of genetic diversity of mtDNA within the conserved Lanyu pigs was demonstrated by low haplotype and nucleotide diversities, supported by Fu and Li's D* neutrality test (1.44055; P < 0.05). The mtDNA control region sequences of extant pigs in the Lanyu Islet, however, showed high haplotype and nucleotide diversity, and clustered with exotic pigs. These results indicate no maternal lineage mtD-NA gene introgression from Formosan wild pigs and introduced exotic pigs to conserved Type I Lanyu pigs, and a severe loss of heterozygosity of mtDNA in conserved Lanyu pigs. The remaining extant pigs on the Lanyu Islet have been introgressed with exotic breeds. Strategies for future conservation of native Lanyu pigs are now even more urgent and important.
兰屿猪是一种原产于台湾东南部兰屿岛的本土品种。1975年和1980年，两群兰屿猪从兰屿岛被引入台湾。目前保种的兰屿猪种群仅由44只遗传谱系不明的动物组成。兰屿猪拥有一个与亚洲和欧洲猪种截然不同的母系遗传谱系。本研究旨在基于细胞色素b编码基因了解保种的兰屿猪、亚洲型猪和欧洲型猪之间的系统发育关系，确定保种的兰屿猪的母系谱系和遗传多样性，并探讨保种的兰屿猪是否发生了外来猪种或台湾野猪的基因渗入。两种类型的兰屿猪的整个线粒体基因组由2个核糖体RNA、22个转运RNA和13个蛋白质编码基因组成。在保种的兰屿猪群中仅鉴定出线粒体DNA（mtDNA）控制区和细胞色素b的2种单倍型。构建最大似然树时，I型兰屿猪的线粒体基因形成了一个独特的分支，其细胞色素b和控制区与亚洲型和欧洲型品种、台湾野猪及外来品种之间的成对距离都很大。单倍型和核苷酸多样性较低表明保种的兰屿猪mtDNA的遗传多样性显著丧失，这得到了Fu和Li的D*中性检验的支持（1.44055；P<0.05）。然而，兰屿岛上现存猪的mtDNA控制区序列显示出高单倍型和核苷酸多样性，并与外来猪种聚类。这些结果表明台湾野猪和引入的外来猪种没有向保种的I型兰屿猪发生母系谱系mtDNA基因渗入，且保种的兰屿猪mtDNA杂合性严重丧失。兰屿岛上现存的其余猪种已与外来品种发生了基因渗入。现在，制定未来保护本土兰屿猪的策略变得更加紧迫和重要。
