Dr. Lutz Roewer is one of the renowned forensic scientists who transformed DNA forensics through studying the Y-chromosome and demonstrating the value of Y-STR analysis for forensic casework. The use of a YSTR profile can help by excluding male suspects, or indicating multiple male contributors, or provide information that can be used to help find an unknown male perpetrator. Additionally, YSTR analysis is done for kinship testing and cases such as missing persons or for identification of victims in mass disasters.
Dr. Roewer is currently an Associate Professor for Forensic Genetics at the Institute of Legal Medicine in the Charité, Berlin (Germany), and Director of the Department of Forensic Genetics at this institute.
He is also the curator of the Y-Chromosome Haplotype Reference Database, also known as the YHRD and is working in various European-funded international projects, like DNASEQEX. Additionally, Lutz is a member of the editorial board of Forensic Science International Genetics and of the advisory board of the International Journal of Legal Medicine.
Dr. Roewer has been a member of the SWGDAM Y-STR Committee for the past 5 years, and last but not least, he has authored more than 130 peer-reviewed articles in scientific journals and publishes regular reviews and chapters in various textbooks.
This September, Dr. Roewer will be presenting at the 31st International Symposium on Human Identification on the YHRD database. Recently, Nicole Siffling, Meeting and Marketing Communications Manager at Promega spoke with him to learn more about the database and future applications of the Y-Chromosome
So Lutz, you told me just recently that the DNA Commission of the ISFG has published the recommendation on the interpretation of YSTR results in forensic analysis, which actually resumes 25 years of YSTR research. What can you tell me about this great paper?
Yeah, the paper appeared just a week ago in a journal called the Forensic Science International Genetics, and it is the final stage of, as you say, 20-25 years of research and collaboration all over the world with crime labs and research departments. They have provided information on YSTRs’ allelic spectrum, information content and so on, in order to solve sexual assault cases.
For courts and for experts, it’s very important to make a correct interpretation of such data. With the final edition of these guidelines, I think we could give a lot of advice and help to those court-going experts from now on (and may I make this point) especially in different jurisdictions. So in different countries in the world. We found solutions based on the context of the jurisdiction of a country, so that a tailor-made solution can be found and interpretation can be done the right way.
Wow, this sounds like a wonderful tool now for the experts.
Now, I would like to come back to the YHRD database. It was launched in 1999 and now hosts more than 307,000 haplotypes from 1,348 sampling locations. Lutz received samples from more than 450 institutes from 135 countries worldwide, which is, I think, amazing. And, on top of that, when the US YSTR database was discontinued, the data was permanently transferred to the YHRD, which makes this YHRD database even more global and great.
So, can you tell me anything new about this database? Is there anything exciting lately?
What’s exciting is that every day we receive data requests and questions on giving advice to regional stakeholders and experts; how to use a confidence interval which they can find in the YHRD, how to find a frequency that they find in the YHRD, and so on. So, this is the most exciting – to have this permanent communication with the community via this database platform.
Apart from this, I wanted to mention that the last 2 weeks we’ve received data from the Republic of Kiribati, which is a small republic in the Polynesian archipelago and from Northern Africa (Burkina Faso), so it shows that not only the big countries, but also the small countries are interested. So, the Forensic Police in the Burkina Faso is interested to use this resource for their local crime finding. It’s amazing that important countries like the US, China, Singapore, and Germany focus on this database as their preferred resource for reference material. So, they’ve coined their guidelines in a way that that YHRD is the advised reference material. And when you see the differences of these countries, and you see the successes of the approach, we are very happy with that.
This is really a great tool and I think you can be proud that you are (I say) the father of this database.
Generally speaking about YSTRs in forensics, do you see anything new that scientists will practice in the near future?
The Y-Chromosome is a multi-purpose tool. You can resolve mixtures. You can match male suspects to traces, and so on. This is well known for decades. However, it is also well known that it is very important or very useful to trace back in time the lineage of a person. So you can get some information on a person’s ancestry, because it’s very nicely embedded in the Y-Chromosome structure or the mutation profile where this person geographically, and ethnically, and linguistically comes from. So you can even trace the language of a person (which you’d never know) only from a hair using the Y-Chromosome; where the ancestors of this person probably lived and which languages they speak and so on. So, that could be, of course, a big help to crime labs and police in severe cases where clues aren’t available for an unknown suspect. You can get more background context out of a trace, which is crucial for the case.