Telomere Shortening Of Leukocytes And The Application In Age Estimation Of Forensic Medicine

Objective To discuss the relationship between the length shortening of telomere in people's periphery blood leucocyte and human age /sex , and the influence of tissue autolysis to telomere length of leucocyte measured by southern blotting. To evaluate the medicolegal value of deduce the human age by measuring the length of telomereMethods 1.Correlated study between telomere length and human age Ninety-seven peripheral blood samples were divided into three groups according to the age: the age between twenty and forty; the age between forty to sixty; and above sixty age. Extracted the telomere DNA of human periphery blood leucocyte by phenol- chloroform methods, measure the length of restriction fragment in telomere DNA. 2. The influence of tissue autolysis to telomere length Six blood samples which were the same age(twenty-seven years old) and same sex(male) were all 3ml, every blood sample were divided into three equal parts, and discern to extracted the telomere DNA instantly,after 24 hours and 72 hours set into the climate case, then measure the mean length of restriction fragment in telomere DNA.Results 1.Correlated study between telomere length and human age The average length of TRF is shorting gradually with age increasing; and there are statistics differences among different groups (P<0.05) by SNK tests; and T-test for different sex's TRF value show that there are statistics sexual differences in groups of age between forty to sixty and age above sixty(P<0.05); There is favorable correlated relationship between age and the average TRF value, y=-0.054x+11.16 (R2=0.64); linear analysis between age and the average TRF value in different sex group show: y=-0.069x+11.67 (R2=0.71) (male) and y =-0.39x +10.62 (R2=0.69) (female) . 2. The influence of tissue autolysis to telomere length SNK-tests to average TRF values in different tissue autolysis groups show: there are statistics differences between 72 hours groups and 24 hours groups / instantly groupsConclusion The average length of TRF is shorting gradually with age increasing; There is sexual difference in the process of telomere DNA shorting, velocity of telomere DNA shorting is different with different sex, velocity of telomere DNA shorting in man is faster than woman; The influence of tissue autolysis to velocity of telomere DNA shorting is comparatively large. So we concluded that the feature of telomere length shortening in human leukocytes can be utilized in forensic age deducing and we should consider the influence of blood autolysis.