Table of contents
  1. The searching step
  2. Reduction step

Finding Criminals Through DNA of Their Relatives

Brenner, Bieber, Lazer, Science, 2 June 2006, (10.1126/science.1122655)

Discussion of the Science paper

Synopsis –

If a crime stain isn't matched in the offender database, there's still a good chance that its relative is there. The relative can likely be found by "kinship" searching if you know how to search. If the search results in a list of even dozens of potential relatives, sort them out with Y-haplotyping. This approach could significantly increase the effective reach of offender database. It could also raise some hackles and some eyebrows.

Comments – We discuss a hybrid searching approach consisting of two steps:

  1. Search a crime stain profile against an offender database looking for possible relatives of the crime stain donor;
  2. Reduce the list of candidate relatives.

  1. The searching step
  2. There has been some misunderstanding about the nature of the suggested searching step, partly from colleagues who assume what we propose is related to the "low stringency" method presently implemented in the CODIS software used by law enforcement in the US. It isn't. It's radically different both in implementation and, more importantly, in performance.

    The searching is done using the set of markers on which the database was built. The only hurdles to begin searching tomorrow are

    1. to install the proper searching software in place of CODIS
    2. to have permission from the public, the database administration or the legislature – whomever is deemed relevant – to do the familial search.

  3. Reduction step
  4. Y-haplotyping is all the rage. Many forensic laboratories have Y-haplotyping capability or are interested in developing it. Therefore this method of reduction is immediately feasible for many states.