In police investigation, description of the morphology of the suspect can be deceptively misdescriptive.

Also in 2015 the Laboratory of Hematology Forensic has proposed a new analysis to assist forensic investigation: Highlighting morphological characters to a person from a biological trace found on the crime scene (eye, skin and hair color).

This analysis is based on Study of SNPs (Single Nucleotide Polymorphism) in genes involved in pigmentation mechanisms.

For this study the laboratory selected three hundred thirty-seven volunteers with different phenotypic traits. All samples were collected according to the guidelines approved by ethics committees in France.

In this method we built classification:

• Three categories with SNPs of known association with eye color phenotypes: blue, brown and intermediate.
• Six models with SNPs of known association with skin color phenotypes between fair skin and dark skin
• Seven categories with SNPs involved in hair color: Red hair vs. dark hair

The analysis of SNPs was undertaken using Snapshot chemistry and capillary electrophoresis. A set of twenty-six SNPs from twelve different genes was selected to perform it.

The laboratory has set up a database (Filemaker Software) for storing the genetic and phenotypic data of all those volunteers. This developed tool helps to predict morphological traits to a person from biological material found at crime scenes.

Background: The use of DNA evidence in criminal investigations has gained worldwide acceptance in recent decades. During the last years in Mexico, reports of missing persons have increased dramatically due to the abrupt rise of violent crimes. The situation goes far beyond the current technological response capacity in the country and it exposed a second challenge in the form of increased social pressure on the government coming from the relatives of missing people: they seek to find any remaining of their beloved ones. Therefore, we implemented the FICHA project. Methods: A total of 190 blood samples from relatives of missing people in northeastern Mexico were genotyped and analyzed using a multiplex STR system. Results (statisticals) and conclusions: some of the profiles obtained served as an aid in the resolution of cold cases.

Cannabinoid gas-phase detectors were assembled modifying piezoelectric quartz crystals with Fast Blue B salt, Triton X-100, and Nafion-coated Fast Blue B salt. A similar sensor was assembled using cucurbit (6) nuril for modifier to detect cocaine in the gas-phase. Several analyses were carried out with seized drug samples, and the amount of cannabinoids or cocaine adsorbed on the sensors was calculated using Sauerbrey equation. Moreover, PM7 semi empirical calculations were used to understand the adsorption processes in these systems. Fast Blue B salt coated with a thin Nafion layer for cannabinoids and cucurbit (6) uril for cocaine provided stable and reversible responses during the analyses of several seized samples. Theoretical calculations support their affinity towards the analytes, and our results show that it is possible to assemble reliable piezoelectric sensors for cannabinoids and cocaine.

Carbon monoxide is a euphoric toxic gas with the propensity of causing death within a short time interval. In this study, eighteen (18) rabbits of same sex and age were divided into three groups thus: Carbon monoxide Death (CD) group was made up of animals exposed to high levels of Carbon monoxide (CO) till death, while Disguised Death (DD) group composed of animals mechanically sacrificed and exposed to carbon monoxide. Similarly Control Group (CG) was comprised of animals mechanically sacrificed without exposure to carbon monoxide. Vitreous humour samples were extracted from the animals and their lipid profiles determined using standard methodologies. Pearson correlation analyses were used to establish relationships between vitreous lipid profile components and the acute graded carbon monoxide concentrations. Results showed a significant decrease (P<0.05) in the vitreous lipid profile of the studied groups. The decrease in vitreous humor lipid profile was more pronounced in CO death than disguised death. Hence a markedly decreased vitreous lipid profile could serve as an adjunct hallmark in the investigation of CO poisoning death.

Global and gene-specific variation in DNA methylation has been observed between human populations. However, to our knowledge, differences in DNA methylation between South African ethnic groups have not been reported before. The present study aimed to determine if there was differential methylation in previously reported gene-specific markers between four groups. Saliva was collected from 42 healthy individuals, belonging to Black, Indian, White and Coloured ethnicities. A multiplex Methylation-Sensitive Restriction Enzyme (MSRE)- PCR assay was used to determine methylation levels of CpG sites in the USP49, DACT1, L81528 and PFN3 genes. The Coloured ethnic group displayed highest methylation levels for all selected markers, whereas the Black ethnic group showed lowest. DACT1 and L81528 markers displayed significant variations between ethnic groups (p=0.02 and p=0.03, respectively). Differences in DNA methylation levels between populations all over the world could potentially assist forensic analysts to accurately narrow down the search to ethnicity of sample donors as well as aid medical scientists in personalised medicine.