Pre-Lab: Using DNA to Identify Human Remains
Problem How can pedigrees help scientists identify human remains?
Lab Manual Chapter 14 Lab
Skills Focus Analyze Data, Draw Conclusions
Connect to the The nucleus is not the only location in a cell where DNA can be found. DNA is also found in the mitochondria of cells. This mitochondrial DNA, or mtDNA, exists as small loops, rather than long strands. Unlike nuclear DNA, mtDNA is inherited only from the mother. Thus, except for mutations, the sequence of nucleotides in mtDNA remains constant over many generations.
Less than one percent of a cell's DNA is mtDNA, but in that percentage are many copies of the small mtDNA molecules. So when forensic scientists cannot collect a suitable sample of nuclear DNA, they look for mtDNA. Usable mtDNA can often be found even after a body decays or is burned. In this lab, you will explore how mtDNA was used to help confirm the identity of bones that scientists thought belonged to members of the Romanov family.
Review What is a pedigree?
Explain In a pedigree, what does a circle represent? What does a square represent?
Infer How do you know that mtDNA isn't sorted and recombined during meiosis?
Preview the procedure in the lab manual.
Infer The tsar and tsarina had five children. Did all seven family members have the same mtDNA? Give a reason for your answer.
Predict To confirm that bones belonged to the tsar's children, which living relative would be more useful—a relative of the tsar or a relative of the tsarina? Why?
Infer If two people have the same mtDNA, what can you infer about their biological relationship?
The Romanovs ruled Russia for 300 years until the Bolshevik Revolution of 1918 resulted in the execution of Tsar Nicholas II and his family.
Visit Chapter 14 online to test yourself on chapter content and to find activities to help you learn.
Untamed Science Video The Untamed Science crew identifies the chromosomes that carry genes for colorblindness.
Art in Motion View a short animation that explains nondisjunction.
Art Review Review your understanding of karyotypes with this drag-and-drop activity.
InterActive Art Learn all about pedigrees and how to make them with this animation.
Data Analysis Analyze the connection between type O blood and an increased susceptibility to cholera.
Tutor Tube Why do traits sometimes “skip a generation”? Tune in to the tutor to find out.