The half-life of DNA in bone: measuring decay kinetics in 158 dated fossils.
Claims of extreme survival of DNA have emphasized the need for reliable models of DNA degradation through time. By analysing mitochondrial DNA (mtDNA) from 158 radiocarbon-dated bones of the extinct New Zealand moa, we confirm empirically a long-hypothesized exponential decay relationship. The average DNA half-life within this geographically constrained fossil assemblage was estimated to be 521 years for a 242 bp mtDNA sequence, corresponding to a per nucleotide fragmentation rate (k) of 5.50 × 10(-6) per year. With an effective burial temperature of 13.1°C, the rate is almost 400 times slower than predicted from published kinetic data of in vitro DNA depurination at pH 5. Although best described by an exponential model (R(2) = 0.39), considerable sample-to-sample variance in DNA preservation could not be accounted for by geologic age. This variation likely derives from differences in taphonomy and bone diagenesis, which have confounded previous, less spatially constrained attempts to study DNA decay kinetics. Lastly, by calculating DNA fragmentation rates on Illumina HiSeq data, we show that nuclear DNA has degraded at least twice as fast as mtDNA. These results provide a baseline for predicting long-term DNA survival in bone.
Ancient DNA Laboratory, School of Biological Sciences and Biotechnology, Murdoch University, 90 South Street, Perth, Western Australia 6150, Australia. morten.allentoft@gmail.com
Morten E
ME
Allentoft
Matthew
M
Collins
David
D
Harker
James
J
Haile
Charlotte L
CL
Oskam
Marie L
ML
Hale
Paula F
PF
Campos
Jose A
JA
Samaniego
M Thomas P
MT
Gilbert
Eske
E
Willerslev
Guojie
G
Zhang
R Paul
RP
Scofield
Richard N
RN
Holdaway
Michael
M
Bunce
D000818:Animals; D001717:Birds / Q000235:genetics*; D001842:Bone and Bones / Q000502:physiology*; D004272:DNA, Mitochondrial / Q000032:analysis* / Q000235:genetics / Q000378:metabolism*; D005580:Fossils; D006207:Half-Life; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008957:Models, Genetic; D009520:New Zealand; D055110:Radiometric Dating; D060888:Real-Time Polymerase Chain Reaction; D013696:Temperature
D004272:DNA, Mitochondrial