Ancestry informative markers

Have you guys seen the commercials about ancestry DNA from ancestry.com, my heritage, and 23andme? Ancestry informative markers (AIMs) have been around for a long time but it is only coming into light in the public eye because of these companies trying to make a profit. I've even fallen for the mystery of discovering my own ancestry, although I am pretty sure it will only tell me that I am full European (duh!). 

In missing persons or mass disaster situations, the biggest concern is identifying the remains either through visual examination, dental and/or medical records, or STR typing. DNA analysis is typically a last resort because it is time consuming and costly. When all methods have failed and there is low template and highly degraded DNA, alternative solutions are required such as DNA phenotyping (see previous blog) and lineage markers, to name a few. Mitochondrial DNA and Y chromosome DNA are examples of lineage markers that can provide useful information on the maternal and paternal lineage, respectively. However, because these are haplotypes (a group of genes passed down from a single parent) and non-recombinant genetic markers, individualization is limited especially when whole families are missing. Therefore, analysis of DNA markers from autosomal chromosomes that are small enough for degraded samples are preferred. Biallelic markers called insertions/deletions (INDELS) can be analyzed by targeting very short fragments of DNA less than 200 base pairs. One group of scientists selected 46 AIM-Indels considering allele frequencies from four human population groups: African, European, East Asian, and Native Americans. The developed a multiplex allowing all 46 AIM-Indels to be amplified in a singe PCR reaction. Later, another study evaluated the panel on bones displaying various degrees of DNA degradation. Anthropological examinations and other information regarding the individual was provided prior to testing. They found that samples from non-admixed individuals were successfully assigned to their continental group. Samples from admixed individuals were assigned with an estimate of the proportion of co-ancestry. Of course, there is ethical and confidentiality concerns with this type of analysis. The scientists conclude that although this type of information may be extremely useful in several scenarios (forensic or genetic populations studies), this type of information is sensitive and should only be used for the purpose of victim identification.

However, I found an interesting article about the use of AIMs as a tool to combat illegal trafficking of human kidneys. Human organs can extend and improve the lives of people, but the demand is so high and the supply so low. This has created the basis for a black market that is highly profitable at selling organs. Some people sell their organs when their families are in financial distress. Some countries have been known to donate organs of executed prisoners. Even worse, people have been murdered for their organs. Analysis of AIMS could be useful in cases when donor and recipient are from different origins or when the origin of the donor is unknown.




References:
Romanini C, et al. Ancestry informative markers: Inference of ancestry in aged bone samples using an autosomal AIM-Indel multiplex. FSI: Genetics 16 (2015) 58-63.

Pereira R, et al. Straightforward inference of ancestry and admixture proportions through ancestry-informative insertion deletion multiplexing. PLoS ONE (2012) 7(1)

Severini S et al. Use of ancestry-informative markers as a scientific tool to combat the illegal traffic in human kidneys. FSI: Genetics Supplement Series 5 (2015) e302-e304.