DNA methylation from bloodstain as a forensic age estimation method

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DNA illustration. (Source: IDN Times)

Age estimation is very important in forensic analysis, which is often performed based on the analysis of bones and teeth. However, identification of bones and teeth can only be done when human skeletons are available identification.

The methylation of DNA is one way of estimating the age of biological samples. The methylation of DNA is the best epigenetic modification way of estimating the age of biological samples in humans because the DNA in aging individuals resembles the development set in a tightly controlled process by specific epigenetic modifications.

The methylation of DNA is one way of estimating the age of biological samples. The methylation of DNA is the best epigenetic modification way of estimating the age of biological samples in humans because the DNA in aging individuals resembles the development set in a tightly controlled process by specific epigenetic modifications. The process is found only at the position of 5 pyrimidine rings of cytosine in the order of CPG dinucleotide.

This type of research is descriptive with the number of samples as many as ten samples with different age variations in each type of gender. The stages of the research start from sampling the blood that is confirmed to be healthy and in isolation using DNAzol and chloroform.

After the study ended where the total number of collected samples amounted to 10 samples, methylation percent of male subjects tended to increase in harmony with the age categorization. However, it was decreasing in elderly subjects and very likely to be influenced by lifestyle, environmental, and disease factors. As for the subjects of women, methylation percent has consistently increased according to age categorization, although the rate of increase is not constantly measurable.

Between males and females, CpG’s sites have significantly different levels of DNA methylation. This CpG site is placed on an autosomal chromosome with an absolute difference in methylation because CpG sites are relocated on the X chromosome. Hence, the gender-specific methylation differences in the X chromosome tend to be more unstable. Female susceptibility to stress and certain diseases also significantly affect the rate of DNA methylation, so that the factors affecting the production of DNA vary widely in each individual (Davegårdh et al. 2019).

Degenerative diseases and metabolic syndrome owned by each individual also dramatically affects the outcome of percent of methylated DNA. The travel process of degenerative diseases targets the cellular epigenetic machine elements, altering the expression and activity of the epigenetic machine to affect the changes in the epigenetic state of each individual (Neidhart 2016).

An epigenome Regulator that is often overlooked is neuroendocrine, whereas DNA methylation can be a dynamic process, where individual hormonal conditions strongly affect the role of hydroxymethylation of cytosine. The use of certain oxidative or antioxidant medications will also affect the Histon modification rate. It can occur, for example, through cytosine mutations in case they are dimethylated in normal cells. The absence of cytosine-etteration can lead to permissive histone modifications and allow the gene to be expressed. This type of mechanism can change the phenotype and behavior of cells (Neidhart 2016).

Neoplastic, degenerative, metabolic, even inflammatory diseases will cause oxidative stress that will affect the activation and inactivation of specific genes, as well as the instability of the genome, which occurs with the epigenetic mechanisms as well. Unlike genetic mutations, the epimutation does not alter the primary sequence of DNA and is potentially reversible (Neidhart 2016). (*)

Author: Ahmad Yudianto

Details of this research available at:

http://journal.fk.unpad.ac.id/index.php/mkb/article/view/1863

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