Department of Biology, Memorial University of Newfoundland, St. John's, NL A1B 3X9, Canada.
Genome. 2011 Feb;54(2):110-9. doi: 10.1139/G10-102.
The island of Newfoundland, the first of England's overseas colonies, was settled from the 17th century onward by restricted numbers of English, Irish, and French immigrants, in small "outport" communities that have maintained geographic, religious, and linguistic isolation to the latest generations. To measure the extent of modification and loss of genetic variation through founder effect, drift, and inbreeding in this historically isolated population, we analyzed the complete mitochondrial DNA (mtDNA) genomes and 14 microsatellite loci from each of 27 individuals with matrilineal ancestries extending to the colonial period. Every individual has a unique mtDNA genome sequence. All but one of these genomes are assignable to one of five major (H,J,K,T, and U) or minor (I) European haplogroups. The possibility of homoplasy at single nucleotide polymorphism (SNP) sites that define subtypes within the H haplogroup is discussed. Observed haplogroup proportions do not differ significantly from those of western Europeans or between English and Irish Newfoundlanders. The exceptional individual is a member of haplogroup A2, who appears to be the descendant of a Mi'kmaq First Nations mother and a French father, a common marriage pattern in the early settlement of Newfoundland. Microsatellite diversity is high (HE = 0.763), unstructured with respect to mtDNA haplotype or ethnicity, and there is no evidence of linkage disequilibrium. There is a small but significant degree of inbreeding (FIS = 0.0174). Collection of whole mtDNA genome data was facilitated by the use of microarray sequencing, and we describe a simple algorithm that is 99.67% efficient for sequence recovery.
纽芬兰岛是英格兰的第一个海外殖民地，从 17 世纪开始，就有数量有限的英国、爱尔兰和法国移民定居在这些小型的“外港”社区。这些社区一直保持着地理、宗教和语言上的隔离，直到最近几代人。为了衡量在这个历史上与世隔绝的人群中，通过奠基者效应、漂变和近亲繁殖导致的遗传变异的程度和损失，我们分析了 27 名个体的完整线粒体 DNA（mtDNA）基因组和 14 个微卫星位点，这些个体的母系祖先可以追溯到殖民时期。每个个体都有一个独特的 mtDNA 基因组序列。除了一个个体之外，这些基因组都可以归属于五个主要的（H、J、K、T 和 U）或较小的（I）欧洲单倍群之一。还讨论了在定义 H 单倍群亚型的单核苷酸多态性（SNP）位点上发生同形现象的可能性。观察到的单倍群比例与西欧人或英格兰和爱尔兰纽芬兰人之间没有显著差异。异常个体是单倍群 A2 的成员，他似乎是一名米克马克第一民族母亲和一名法国父亲的后代，这是纽芬兰早期定居的常见婚姻模式。微卫星多样性很高（HE = 0.763），与 mtDNA 单倍型或种族无关，并且没有证据表明存在连锁不平衡。存在着微小但显著的近亲繁殖程度（FIS = 0.0174）。微阵列测序促进了整个 mtDNA 基因组数据的收集，我们还描述了一种简单的算法，其序列恢复效率为 99.67%。
