Chapter 11

Advanced Topis in DNA Analysis 

This chapter delves deeper into current topics in DNA analysis.  It’s a more advanced chapter that is built upon the foundation from the last one, so be sure you are comfortable with that material.  Our focus will be on two topics – complex mixtures and lineage markers.   

The analytical techniques used in DNA profiling have been constantly improving, reaching lower and lower detection limits.  This can be a mixed blessing in that trace amounts of DNA that might not have been detected years ago are now recoverable. More information results but sorting the relevant from irrelevant has become more challenging as a result.  We will touch upon difficulties and opportunities presented by trace levels of DNA that lead to complex mixtures.   

Lineage markers are DNA fragments that are passed on from one parent to a child. Mitochondrial DNA comes from our mothers (the maternal line).  Men carry Y-STRs from their fathers (the paternal line). We will see how lineage markers are utilized in forensic situations.  We will also touch upon investigative genetic genealogy and the use of probabilistic software used for mixture analysis. 

Learning Objectives

11.1 Describe the fundamentals of DNA as transfer and trace evidence and the concept of low copy number. 

11.2 Recognize the characteristics of simple and more complex DNA mixtures 

11.3  Appreciate the advantages and limitations of probabilistic genotyping software for mixture interpretation. 

11.4 Differentiate between the different lineage markers used in forensic settings such as missing persons cases. 

11.5 Understand basic features of investigative genetic genealogy.