Subclade
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In genetics, a subclade is a subgroup of a haplogroup. Subclades are often referred to in genealogical DNA tests of human mitochondrial DNA haplogroups and human Y-chromosome DNA haplogroups, where they represent subbranches of major branches on the human family tree.[1]
Naming convention[edit]
Although human mitochondrial DNA (mtDNA) and Y chromosome DNA (Y-DNA) haplogroups and subclades are named in a similar manner, their names belong to completely separate systems.[2]
mtDNA[edit]
mtDNA haplogroups are defined by the presence of a series of single-nucleotide polymorphism (SNP) markers in the hypervariable regions and the coding region of mitochondrial DNA. They are named with the capital letters A through Z, with further subclades named using numbers and lower case letters.[2][3][4]
Y-DNA[edit]
Y-DNA haplogroups are defined by the presence of a series of SNP markers on the Y chromosome. Subclades are defined by a terminal SNP, the SNP furthest down in the Y chromosome phylogenetic tree.[5] The Y Chromosome Consortium (YCC) developed a system of naming major human Y-DNA haplogroups with the capital letters A through T, with further subclades named using numbers and lower case letters (YCC longhand nomenclature). YCC shorthand nomenclature names Y-DNA haplogroups and their subclades with the first letter of the major Y-DNA haplogroup followed by a dash and the name of the defining terminal SNP.[6] Y-DNA haplogroup nomenclature is changing over time to accommodate the increasing number of SNPs being discovered and tested, and the resulting expansion of the Y chromosome phylogenetic tree. This change in nomenclature has resulted in inconsistent nomenclature being used in different sources.[7] This inconsistency, and increasingly cumbersome longhand nomenclature, has prompted a move towards using the simpler shorthand nomenclature.
Further reading[edit]
- "DNA Learning Center:Databases: Understanding Haplogroups, 'Deep Ancestry Part I'". DNA Ancestry Project. Retrieved 14 February 2015.
See also[edit]
References[edit]
- ^ "Understanding Results: Y-DNA Single Nucleotide Polymorphism (SNP): What is a Y-chromosome DNA (Y-DNA) haplogroup?". Family Tree DNA. Retrieved 31 March 2013.
Y-chromosome DNA (Y-DNA) haplogroups are the major branches on the human paternal family tree. Each haplogroup has many subbranches. These are subclades.
- ^ a b "Understanding Results: mtDNA: How are mitochondrial DNA (mtDNA) Haplogroups named?". Family Tree DNA. Retrieved 3 April 2013.
- ^ "About mtDNA Haplogroups (Maternal Ancient Ancestry)". DNA Ancestry Project. Retrieved 1 April 2013.
- ^ "Comparison of Y-DNA and mtDNA haplogroups". DNA Ancestry Project. Retrieved 1 April 2013.
- ^ "myFTDNA 2.0 User Guide: Y-DNA: What is the Y-DNA - Matches page?". Family Tree DNA. Retrieved 31 March 2013.
A terminal SNP determines the terminal (final) subbranch on the Y-DNA Tree to which someone belongs.
- ^ "Understanding Results: Y-DNA Single Nucleotide Polymorphism (SNP): How are haplogroups and their subclades named?". Family Tree DNA. Retrieved 31 March 2013.
- ^ "Understanding Haplogroups: How are the haplogroups named?". Family Tree DNA. Retrieved 31 March 2013.
