{"id":200,"date":"2025-03-31T12:56:31","date_gmt":"2025-03-31T12:56:31","guid":{"rendered":"http:\/\/localhost\/forensicscience\/?page_id=200"},"modified":"2025-11-12T11:19:15","modified_gmt":"2025-11-12T11:19:15","slug":"chapter-9","status":"publish","type":"page","link":"https:\/\/staging.routledgelearning.com\/forensicscience\/chapter-9\/","title":{"rendered":"Chapter 9"},"content":{"rendered":"\n
\n

Biological Evidence<\/strong><\/h3>\n\n\n\n
\n
\n

If this book had been published in 1990, this chapter would be covering the cutting edge of forensic biological testing and identification.  Now the procedures and methods we will explore are used as primarily as screening tests.  This does not mean that these tests and results are not important \u2013 they are vital, and we will explore why.   <\/p>\n\n\n\n

We will talk about biological fluids targeted in forensic science including blood, saliva, semen, and urine. Tests evolved to target specific components in these fluids, but all are subject to false positives and false negatives.  Much of the chapter focuses on blood including some of the basic genetics behind traits such as blood type.  Although not used forensically, these methods are based on the same genetic principles underlying DNA profiling.  Think of this chapter as the warm-up to the DNA events to come.   <\/p>\n\n\n\n

Learning Objectives<\/h3>\n\n\n\n

9.1 Describe the biological fluids targeted in forensic science <\/p>\n\n\n\n

9.2 Understand the nature of presumptive testing and concepts of false positives and false negatives <\/p>\n\n\n\n

9.3 List the common presumptive tests for blood <\/p>\n\n\n\n

9.4 Describe the fundamentals of immunological testing and how they are implemented in forensic settings <\/p>\n\n\n\n

9.5 List the common test methods for semen and saliva <\/p>\n\n\n\n

9.6 Understand the basic genetic concepts associated with genetic marker systems <\/p>\n\n\n\n

9.7 Understand and be able to perform simple combined probabilities given population frequencies<\/p>\n<\/div>\n\n\n\n

\n

Quiz Quick Links<\/h3>\n\n\n