Salty or sweety? Alternatives for bone preservation along extended periods of time

Abstract

Sodium chloride is an effective human corpse tissue preservation medium due to its hygroscopic features and other phyco-chemical characteristics. We present herein sucrose as an alternative material for this purpose. Both media: solid Sodium Chloride and sucrose were tested comparing their efficiency as preservation alternatives. We used a set of 18 phalanges of a female hand buried for over ten year in a sealed coffin. After exhumation, 9 phalanges were preserved in sugar and 9 in salt, individually stored in 15 ml polypropylene tubes at room temperature for 4 years. DNA was extracted by three methods: a- total bone decalcification; b- total demineralization and c- purification by a semi-automated process. Quantification was performed by fluorimetry (F), Plexor (P) and with an “in house” method (H). Amplification was performed with Global Filer and detected in an ABI 3500. DNA yield by method a- (F: 1.36 ± 0.93 ng/ul; P:0.23 ± 0.18 ng/ul) was higher than for b- (F:0,99 ± 0.31 ng/ul; P: 0,14 ± 0.13 ng/ul) or c- method (not detected). Amplification efficiency was determined by the percentage of complete markers (22 loci), the inter-loci balance _ILB-(Shannon Entropy; SH: 3.09 as maximum) and intra-locus balance (mean local balance: MLB). The inter-loci balance was higher for preservation in sugar than in salt (SH: 1.69 vs 1.07) while MLB values did not show significant differences (0.88 vs. 0.89). Degradation ratio correlates with the genetic profile quality. Sugar, as an alternative conservative medium combined with DNA extraction by method a- showed an optimal strategy to obtain good quality genetic profiles.