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Does The State Say It Is Your DNA?

On Behalf of | Feb 5, 2018 | Criminal Defense |

Does the State say they have DNA evidence against you?  The case does not end there. What kind of DNA is it? How good was the sample? Where was it found, and how did it get there? These are questions Hayes and Ruemmele are prepared to investigate.

Here are a few things you should know:

  1. A person sheds about 400,000 skin cells per day.
  2. DNA may be recovered from skin cells.
  3. Skin cells move around and can be transferred.
  4. A DNA profile can be obtained from as few as 3-5 skins cells, and maybe even from just one skin cell.
  5. Skins cells can be transferred to an item that a person never touched.
  6. The mere presence of DNA does not tell how it got there.
  7. The improper handling of DNA has led to erroneous results and false convictions.
  8. The failure to understand the limitations of DNA evidence and the failure to properly questions DNA witnesses has led to wrongful convictions.

The Limited Value of DNA in Some Cases

Autosomal DNA  is a term used to describe DNA which is inherited from  the autosomal chromosomes. An autosome is any of the numbered chromosomes, as opposed to the sex chromosomes. Humans have 22 pairs of autosomes and one pair of sex chromosomes (the X chromosome and the Y chromosome). For each of the twenty-two pairs of autosomal chromosomes, a person will receive one from the mother and one from the father. Before these chromosomes are passed down, the contents are randomly jumbled in a process called “recombination.”

There is another type of testing called Y-STR testing, which isolates the male DNA. This is sometimes done when there is a mixed sample, and there is insufficient DNA for conventional Autosomal testing. Y- STR DNA profiles are derived from the Y chromosome, which is passed on largely intact from a father to all male offspring, from generation to generation without changing (unless there is a mutation).   Every male in the line—fathers, sons, brothers, uncles, first, second, third, and fourth cousins and all widely dispersed male paternal relatives — will share the same Y-STR profile.

A match for Y-STR does not carry the power that a match from autosomal DNA does, especially in local communities that have remained largely intact and isolated for many generations. Y- STR profiles cluster geographically. Some Y-STR profiles are very common in certain geographic locales.

The statistics that usually accompany DNA results are based on the US at large, and do not account for the concentration of Y-STR DNA that may be present in smaller regions where a small number of families first settled the area and have remained there to the present day.   Y-STR DNA testing is a powerful tool to exclude a person, but is very misleading when used to identify a person. Without proper tools to explain to the judge or jury the limitations of this type of DNA, serious errors in the process may occur. Don’t let that happen in your case.

HAYES RUEMMELE LLC knows how to defend against a case based on DNA. Call us to assist you. 317-978-9779