November 24, 2012

Lack of β thalassemia mutations in Minoan Cretans

Blood Cells, Molecules, and Diseases Volume 48, Issue 1, 15 January 2012, Pages 7–10

A search for β thalassemia mutations in 4000 year old ancient DNAs of Minoan Cretans

Jeffery R. Hughey et al.

Ancient DNA methodologies can be applied in the investigation of the genetics of extinct populations. A search for beta thalassemia mutations was performed on 49 Minoan individuals from the Bronze Age who were living in the island of Crete approximately 4000 Years Before Present (YBP). Standard precautionary measures were employed in the laboratory to ensure authenticity of the DNA extracted from the ancient bones, resulting in the successful analysis of DNA of 24 Minoans. DNA sequencing focused on the Intervening Sequence 1 (IVS-1) of the beta globin gene and its splicing junctions. 63% of the thalassemia mutations observed among modern Cretans reside in beta IVS-1. None of the Minoan individuals carried one of the IVS-1 mutations known to cause beta thalassemia; however, only one was expected to be observed if the average frequency of beta thalassemia heterozygotes in the Minoan population was the same with that of modern day Cretans (7.6%). One individual contained a C to G substitution in position 91 of the IVS-1, located 40 bp 5′ to the intron 1/exon 2 junction. Functional studies indicated that the mutation did not affect mRNA splicing or stability, and most likely represented an innocent single nucleotide polymorphism.

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2 comments:

George said...

West-Nostratic populations (or Indo-Kartvelians) were carrying this mutations?

Ezr said...

The mutation must be related to protection against malaria in (former) malarial areas of the Mediterranean/West Asia. Resistance to malaria typically brings with it the side effect of susceptibility to hemoglobin disorders: sickle-cell anemia in Sub-Saharan Africa and Thalassemia in the Mediterranean/West Asia.

And as the authors themselves acknowlodge, statistically, the absence of the mutation in such a small sample is not unexpected at all.