Archival Notice
This is an archive page that is no longer being updated. It may contain outdated information and links may no longer function as originally intended.
Home | Glossary | Resources | Help | Contact Us | Course Map
Stochastically induced heterozygote imbalance may be observed in STR analysis due to the effective low copy number of DNA templates in degraded DNA.
The amplification process can produce many copies from a relatively low quantity of DNA. If too small a quantity of DNA is introduced at the beginning of amplification, it is possible that heterozygous alleles may amplify differentially. The first few cycles of the amplification process are extremely important; if imbalanced amplification occurs, it will result in stochastic effects.
An analyst can assess the data by calculating the heterozygosity of alleles. If the heterozygote balance is less than 70%, this could indicate a mixture and/or stochastic amplification. Laboratories evaluate the threshold at which these stochastic effects may be more prevalent. This stochastic threshold is used by the scientist to evaluate when alleles of a heterozygote pair may not be detected and plays an important role in the interpretation of DNA profiles.
Review the YouTube Terms of Service and the Google Privacy Policy
Additional Online Courses
- What Every First Responding Officer Should Know About DNA Evidence
- Collecting DNA Evidence at Property Crime Scenes
- DNA – A Prosecutor’s Practice Notebook
- Crime Scene and DNA Basics
- Laboratory Safety Programs
- DNA Amplification
- Population Genetics and Statistics
- Non-STR DNA Markers: SNPs, Y-STRs, LCN and mtDNA
- Firearms Examiner Training
- Forensic DNA Education for Law Enforcement Decisionmakers
- What Every Investigator and Evidence Technician Should Know About DNA Evidence
- Principles of Forensic DNA for Officers of the Court
- Law 101: Legal Guide for the Forensic Expert
- Laboratory Orientation and Testing of Body Fluids and Tissues
- DNA Extraction and Quantitation
- STR Data Analysis and Interpretation
- Communication Skills, Report Writing, and Courtroom Testimony
- Español for Law Enforcement
- Amplified DNA Product Separation for Forensic Analysts