y-chromosome diversity in central africa aussois, september 2005 gemma berniell-lee, jaume...
Post on 18-Dec-2015
214 views
TRANSCRIPT
Y-chromosome diversity in Central Africa
Aussois, September 2005
Gemma Berniell-Lee, Jaume Bertranpetit, David Comas
A HAPLOID SYSTEM
THE Y CHROMOSOME
Inherited via the father
No recombination
Variation passed on in the form of a block
STRs and SNPs
THE Y CHROMOSOME
TACGTAGCTAGCTAGCTAGCTAATGCAC
TTCGTAGCTAGCTAGCTAATGCACGCTA
TACGTAGCTAGCTAGCTAGCTAATGCAC
TTCGTAGCTAGCTAGCTAATGCACGCTA
TACGTAGCTAGCTAGCTAGCTAATGCAC
TTCGTAGCTAGCTAGCTAATGCACGCTA
Set of alleles for a number of STRsHAPLOTYPES
HAPLOGROUPS Set of alleles for a number of SNPs
METHODS
DYS 388
DYS 389 I/II
DYS A7.1
DYS A7.2
DYS 385
DYS 390
DYS 391
DYS 392
DYS 434
DYS 435
DYS 436
DYS 437
DYS 438
DYS 439
DYS 462
DYS 19
DYS 393
EBF MULTIPLEX
MSI MULTIPLEX
CTS MULTIPLEX
RESULTS
FOUNDER BANTU HAPLOTYPEThomas et al.(2000)
DYS 391
109 11
DYS 390
2120 22
DYS 393
1312 14
DYS 392
1110 12
DYS 19
1514 16
Pereira et al.(2002) described three one-step neighbour haplotypes
High frequencies of founder Bantu haplotype and its one-step neighbours in all Bantu populations and identified 3 new ones.
Founder Bantu haplotype in 2 pygmy samples and a one-step neighbour in one pygmy sample.
RESULTS
POPULATION GENETIC RELATIONHIPS
Multidimensional Scaling Plots of RST genetic distances
Stress 0.11
Stress 0.08
RESULTS
POPULATION GENETIC RELATIONHIPS
Multidimensional Scaling Plots of RST genetic distances
POPULATION STRUCTURE
RESULTS
RESULTS
PHYLOGENETIC RELATIONSHIPS
Phylogenetic network of Y-chromosome haplotypes carrying the allele 13.2 of DYS 385
Estimated date of appearance ~5,500 +/- 1,300 years ago.
CONCLUSIONS
Bantu populations from Central Africa are very homogeneous, whilst Pygmy populations seem to be quite diverse.
Bantu populations are statistically different from Pygmy populations
Evidence of possible admixture events between Pygmy and Bantu populations, pointing towards a Bantu-to-Pygmy flow of paternal lineages
No evidence of the Fang population or any of the Bantu populations in our sample set having an origin other than Bantu
FUTURE WORK
Define genetic diversity present at Y-SNP level
48 Y-SNP multiplex reaction
FUTURE WORK