H14: An Introduction

FTDNA-hosted site is mtDNA Haplogroup H Project: H14

Mitochondria are semi-independent entities found in human cells. They work to produce energy for the cell.

Mitochondrial DNA is inherited only from our mothers. Every child inherits a colony of mitochondrial DNA from their mother in her egg cell. The male sperm cell has its own mtDNA. In humans, it does not survive to be passed on.

Mitochondrial DNA is made up of a control region and a coding region. The control region is further divided into two segments. Because the control region has a higher mutation rate than the coding region the segments are called the hypervariable regions. In most journal articles hypervariable region will be abbreviated to HVR. Thus they are HVR1 and HVR2.

Mitochondrial DNA is abbreviated to mtDNA.

A mutation is a change in the mtDNA sequence. Mutations are described in terms of the first human mtDNA to be fully sequenced. Because it was sequenced at Cambridge University it is called the Cambridge Reference Sequence, CRS.

This is an example of a change at the third place in the mtDNA. The change in the sample is shown in bold.

There are are multiple ways to write this. The first is to give the position and then the change: 003C. The second is to give the normal value for CRS, the position, and then the change: T003C. When talking about a single change the second method is clearer. When describing all of the changes found in a sample though it is quicker to use the first method. Some papers place both the normal CRS value and the mutation value after the position. They then indicate the change with an arrow: 003T→C.

An insertion is when an additional segment is added to the DNA sequence. Insertions are described by writing the position, a period, the insertion point and the name of the new segment. Here is an example of the common insertion 315.1C.

Insertions are highly variable and may occur in variable degrees in the same person.

A deletion is when a single segment is removed from the DNA sequence. Deletions are described by writing the position and a minus sign, ”-.” Here is an example of the common pair of deletions at 522 and 523.

Deletions are highly variable and may occur in variable degrees in the same person.

A transition is when one segment is changed to another of the same type.

A→G, G→A, T→C, and C→T are transitions. Here is an example of the transition A263G.

Transitions do not happen that often but they are more frequent than transpositions.

A transposition is when a segment changed to another of the opposite type.

A→T, T→A, C→G, and G→C are transpositions. Here is an example of the transpositon A227T.

Transpositions are uncommon.

A haplotype is a list of the mutations for an individual in relation the the CRS. The haplotype may be the HVR regions or the entire mtDNA sequence.

A Haplogroup is a collection of related samples. mtDNA Haplogroups are usually defined by changes to the slower coding region. Haplogroup H is defined by two mutations, A2706A and C7028C. Because the CRS was an H these two defining mutations will not show up on a list of coding region mutations for Hs.

Here is a typical list of coding region mutations for an H14. Back Soon..

All Haplogroups interconnect forming a single tree of decent from our common formother.

L → L1 → L3 → N → R.

R is a Macro-Haplogroup whose daughter populations span much of the Northern Hemisphere.

Based on the tree from the National Genographic Project public partition database, Behar 2007, this is a basic outline of the R Macro-Haplogroup tree.

• R {C12705C}
  • R*
  • R0* {G11719G} [aka pre-HV]
    • HV* {C14766T}
      • H {C7028C}
      • V {G4580A}
  • B {8280-}
  • R9 {3970}
  • TJ
    • T {G13368A}
    • J {A12612G}
  • U {A11467G}
    • K {A1811G,G9055A,A12308G,G12372A}

• H {A2706A,C7028C}
  • H*
  • ..
  • H14 {T7645C,A10217G}
    • H14a {C16256T,T16352C}
  • ..

Finnila collected 480 samples from Red Cross offices in several Finnish provinces. Of these 188 were Hs using the 7025AluI restriction site. 31 Hs were selected for an mtDNA full sequence. Any H14s found in Finnila would have been classified as H* or H(xH1,xH2).

Any H5s found in Hernstadt would have been classified as H* or H(xH1,xH2,xH3).

Project membership contains a mixed group of results. There are those who have taken only a basic test placing them in Haplogroup H with HVR1 results. There are some who have extended their testing to HVR2. Many have taken the mtDNA Full Genome Sequence test that includes all of the control and coding regions.

All results considered in this section come from members who have taken ether the mtDNA Haplogroup H subclade test, mt-H, or the mtDNA Full Genome Sequence test, FGS, and are positive for the H14 mutations.