Available resource but difficult for me to make scence

Relation about crime scene and identitas v1 forensics chip

Is the technology "identitas v1 forensics chip" related to microarray technology?

if true ,as I know, different combination of genes are expressed in different parts of our body which means a certain tissue only makes particular types of mRNA.

Then my question raised: How can a CSI crew reconstruct a person's virtual appearance (for example skin color, face structure) by a piece of microarray with limited tissue (for example cells from saliva) and mRNA? I mean saliva cells don't make pigment of our body, so how can the eye color or skin color be presumed, for example?

Otherwise, what is the technique "identitas v1 forensics chip "which allow us to detect several phenotype simultaneously?

According to the information I Know,"identitas v1 forensics chip" it contains hundreds of thousands of short sequences of DNA that binds to SNPs,where the DNA from the crime scene binds to this chip can allow software to reconstruct the appearance of the person of interest.

the chip is the first to provide data on all these traits simultaneously. Other devices can determine at most two at a time – usually eye and hair colour.

  • $\begingroup$ It'recommended to include information in your question rather than just providing the links - could you add some information about this chip to the body of your question? $\endgroup$
    – arboviral
    Aug 12 '16 at 15:43
  • $\begingroup$ Sure! I will try to describe it as best as I could. $\endgroup$
    – Snake
    Aug 13 '16 at 0:30

Interesting question. The answer lies encoded in our DNA. If you take eye color for example, the genes important here are well known. The most important are OCA2, HERC2, SLC24A4 and TYR.

These are involved in different parts of the pigmentation process, any mutations in these genes lead to changes in pigmentation. Since also the variants, which lead to a altered pigmentation are known, you only need to analyze some cells containing genomic DNA from your suspect to check for these mutations (or SNP, single nucleotide polymorphisms).

The same is true for hair and skin color. So if you identify one or several mutations in the MC1R gene, you can be pretty sure, that your suspect is red haired, has pretty light skin and a high chance for green eyes.

This technique doesn't need to know the exact expression of a certain gene, but needs information on the cause for a phenotype (like skin, hair or eye color) and the causative gene.

The "Identitas v1 forensics chip" is a microarray chip, unfortunately, the company website is not really a source for information. You can find some in the New Scientist article you linked. This is basically a microarray (or chip) where all the forensically interesting and known SNPs about how a person looks like are analyzed. It gives basic information (or at least a chance) how a persons looks like, what CSI does in the series is usually widely exagerated.

  • $\begingroup$ Thanks a lot! But I feel sorry for my incomplete and unclear description to my question. I still wonder if "identitas v1 forensics chip" have any connection with microarray and how they work? if true ,how can the SNPs be detected when they don't express? $\endgroup$
    – Snake
    Aug 12 '16 at 14:29

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