Haplogroup BT

Haplogroup BT M91, also known as Haplogroup A1b2 (and formerly as A4, BR and BCDEF), is a Y-chromosome haplogroup. BT is a subclade of haplogroup A1b (P108) and a sibling of the haplogroup A1b1 (L419/PF712).[2]

Haplogroup BT
Possible time of origin	about 150-145,000 years ago[1]
Possible place of origin	Africa[2]
Ancestor	A2-T
Descendants	B-M60, CT
Defining mutations	Page65.1/SRY1532.1/SRY10831.1, M42, M91, M94, M139, M299, P97, V21, V29, V31, V59, V64, V102, V187, V202, V216, V235

Sufficient data is not always available to determine which, if any, member haplogroup a Y chromosome in BT belongs to. For instance, a survey of Y chromosomes in over 2000 men from different parts of Africa[3] reported that 7.5% carried haplogroup BT(xDE, KT), i.e. were members of haplogroup BT but not DE or K; such a sample might or might not include members of haplogroups B, C, or F (excluding K), or some undiscovered branch(es) of BT belonging to none of these.

I. Later Stone Age individuals excavated at Fingira Rock, Malawi, dated to around 6100 years ago (2/2 males), and at Mount Hora, Malawi, dated to around 8000 years ago (1/1 males), all belonged to Y haplogroup BT(xCT)[4] (i.e. they did not belong to haplogroup CT but may have belonged to haplogroup B).

Phylogenetics

The ISOGG tree since 2014 has treated M91 as the defining mutation of BT.[5]

• B M60, M181, P85, P90
• CT P9.1, M168, M294

Prior to 2002, there were in academic literature at least seven naming systems for the Y-Chromosome Phylogenetic tree. This led to considerable confusion. In 2002, the major research groups came together and formed the Y-Chromosome Consortium (YCC). They published a joint paper that created a single new tree that all agreed to use.

The revised y-chromosome family tree by Cruciani et al. (2011) compared with the family tree from Karafet et al. (2008). Cruciani et al. (2011) define BT via M91 and P97, and as a consequence, ISOGG has listed BT since February 2012, and treated M91 as defining mutation for BT since 2014.[6]

See also

• Conversion table for Y chromosome haplogroups
• Genetic genealogy
• Haplogroup D (Y-DNA)
• Haplogroup DE (Y-DNA)
• Haplogroup
• Haplotype
• Human Y-chromosome DNA haplogroup
• Molecular phylogenetics
• Paragroup
• Subclade
• Y-chromosome haplogroups in populations of the world
• Y-DNA haplogroups by ethnic group
• Y-DNA haplogroups in populations of Sub-Saharan Africa

References

1. Kamin M, Saag L, Vincente M, et al. (April 2015). "A recent bottleneck of Y chromosome diversity coincides with a global change in culture". Genome Research. 25 (4): 459–466. doi:10.1101/gr.186684.114. PMC 4381518. PMID 25770088.
2. Cruciani, Fulvio; Trombetta, Beniamino; Massaia, Andrea; Destro-Bisol, Giovanni; Sellitto, Daniele; Scozzari, Rosaria (2011). "A Revised Root for the Human y Chromosomal Phylogenetic Tree: The Origin of Patrilineal Diversity in Africa". The American Journal of Human Genetics. 88 (6): 814–818. doi:10.1016/j.ajhg.2011.05.002. PMC 3113241. PMID 21601174.
3. Ansari Pour, Naser; Plaster, Christopher; Bradman, Neil (2013). "Evidence from Y-chromosome analysis for a late exclusively eastern expansion of the Bantu-speaking people". European Journal of Human Genetics. 21 (4): 423–429. doi:10.1038/ejhg.2012.176. PMC 3598330. PMID 22892538.
4. Skoglund, Pontus; Thompson, Jessica C; Prendergast, Mary E; Mittnik, Alissa; Sirak, Kendra; Hajdinjak, Mateja; Salie, Tasneem; Rohland, Nadin; Mallick, Swapan; Peltzer, Alexander; Heinze, Anja; Olalde, Iñigo; Ferry, Matthew; Harney, Eadaoin; Michel, Megan; Stewardson, Kristin; Cerezo-Román, Jessica I; Chiumia, Chrissy; Crowther, Alison; Gomani-Chindebvu, Elizabeth; Gidna, Agness O; Grillo, Katherine M; Helenius, I. Taneli; Hellenthal, Garrett; Helm, Richard; Horton, Mark; López, Saioa; Mabulla, Audax Z.P; Parkington, John; et al. (2017). "Reconstructing Prehistoric African Population Structure". Cell. 171 (1): 59–71.e21. doi:10.1016/j.cell.2017.08.049. PMC 5679310. PMID 28938123.
5. Y-DNA Haplogroup A and its Subclades - 2012 (BT as subclade of A1b-P108) Y-DNA Haplogroup A and its Subclades - 2014 (BT as subclade of A1b-P108); Y-DNA Haplogroup Tree 2015 (BT-M91 listed as subclade of A1a-M31). ISOGG has listed M42 as a mutation characteristic (but not defining) of BT since 2012.
6. ISOGG Haplogroup A (2012): "BT is shown on this tree, though it is not considered to be a part of Haplogroup A, in order to make it clear that, as a sibling clade of A1b1, BT and all other haplogroups are downstream of A1b. Listed 15 February 2012." (also note that the group labelled "A1b" in the image is the "A0" of ISOGG (2012)).

Phylogenetic tree of human Y-chromosome DNA haplogroups [χ 1][χ 2]
	"Y-chromosomal Adam"
		A00	A0-T [χ 3]
			A0	A1 [χ 4]
				A1a	A1b
					A1b1		BT
							B	CT
								DE						CF
							D	E		C		F
															F1	F2		F3	GHIJK
																				G	HIJK
																					IJK	H
														IJ	K
									I	J		LT [χ 5]		K2 [χ 6]
																L	T		K2a [χ 7]	K2b [χ 8]	K2c	K2d	K2e [χ 9]
																			K-M2313 [χ 10]		K2b1 [χ 11]	P [χ 12]
																			NO		S [χ 13]	M [χ 14]		P1	P2
																		N	O			Q	R
Y-DNA by population Y-DNA haplogroups of historic people Footnotes  Van Oven M, Van Geystelen A, Kayser M, Decorte R, Larmuseau HD (2014). "Seeing the wood for the trees: a minimal reference phylogeny for the human Y chromosome". Human Mutation. 35 (2): 187–91. doi:10.1002/humu.22468. PMID 24166809. International Society of Genetic Genealogy (ISOGG; 2015), Y-DNA Haplogroup Tree 2015. (Access date: 1 February 2015.) Haplogroup A0-T is also known as A-L1085 (and previously as A0'1'2'3'4). Haplogroup A1 is also known as A1'2'3'4. Haplogroup LT (L298/P326) is also known as Haplogroup K1. Between 2002 and 2008, Haplogroup T-M184 was known as "Haplogroup K2". That name has since been re-assigned to K-M526, the sibling of Haplogroup LT. Haplogroup K2a (M2308) and its primary subclade K-M2313 were separated from Haplogroup NO (F549) in 2016. (This followed the publication of: Poznik GD, Xue Y, Mendez FL, et al. (2016). "Punctuated bursts in human male demography inferred from 1,244 worldwide Y-chromosome sequences". Nature Genetics. 48 (6): 593–9. doi:10.1038/ng.3559. PMC 4884158. PMID 27111036. In the past, other haplogroups, including NO (M214) and K2e had also been identified with the name "K2a". Haplogroup K2b (M1221/P331/PF5911) is also known as Haplogroup MPS. Haplogroup K2e (K-M147) was previously known as "Haplogroup X" and "K2a" (but is a sibling subclade of the present K2a). K-M2313*, which as yet has no phylogenetic name, has been documented in two living individuals, who have ethnic ties to India and South East Asia. In addition, K-Y28299, which appears to be a primary branch of K-M2313, has been found in three living individuals from India. See: Poznik op. cit.; YFull YTree v5.08, 2017, "K-M2335", and; PhyloTree, 2017, "Details of the Y-SNP markers included in the minimal Y tree" (Access date of these pages: 9 December 2017) Haplogroup K2b1 (P397/P399) is also known as Haplogroup MS, but has a broader and more complex internal structure. Haplogroup P (P295) is also klnown as K2b2. Haplogroup S, as of 2017, is also known as K2b1a. (Previously the name Haplogroup S was assigned to K2b1a4.) Haplogroup M, as of 2017, is also known as K2b1b. (Previously the name Haplogroup M was assigned to K2b1d.)