Analiza dlake u forenzici

undergraduate thesis

• Title (english): Hair in forensic analysis
• Author: Hana Košćec
• Mentor: Inga Marijanović (mentor)
• Granter: University of Zagreb; Faculty of Science; (Department of Biology); Zagreb
• Defense date and country: 2020-08-09, Croatia
• Scientific / art field, discipline and subdiscipline: NATURAL SCIENCES; Biology

Abstract

Dlaka je jedna od glavnih karakteristika sisavaca. Raste iz folikula u dermi i prolazi kroz tri faze: anagen, katagen (faze rasta) i telogen (faza mirovanja) nakon kojeg dlaka prirodno ispada i ciklus se ponavlja. To periodično ispadanje dlaka jedan je od razloga zašto je često pronađena na mjestu zločina. Također može biti iščupana u fazi aktivnog rasta i tada postoji velika mogućnost da na korijenu ima ostatak folikularnog tkiva koje je bogat izvor DNA. Forenzička analiza dlake obično započinje makroskopskom i mikroskopskom analizom nakon kojih slijedi DNA analiza. Da bi poslužila kao validan dokaz dlaka mora biti pravilno sakupljena sa mjestu zločina i pohranjena u laboratorij zajedno s referentnim uzorcima. Na dlaku mogu utjecati brojni vanjski uvjeti zbog čega je poželjno da referentni uzorak bude sakupljen u isto vrijeme kad i onaj koji se ispituje. Za uspoređivanje dva uzorka koristan je usporedni mikroskop koji se sastoji od dva svjetlosna mikroskopa povezana optičkim mostom. Osim usporedbe nepoznate i referentne dlake, mikroskopska analiza može dati informacije o području rasta dlake, rasi i je li nasilno iščupana. U otkrivanju dobi i spola ili pak individualizaciji neophodna je DNA analiza, koja je moguća ako se iz folikularnog tkiva ili korijena dlake uspije izolirati nuklearna DNA. Ako dlaka nema ni folikularni privjesak ni korijen ili kada je ekstrahirane DNA vrlo malo (ili je degradirana), pomoć pri identifikaciji može pružiti mtDNA, no ona ne može poslužiti za individualizaciju jer se naslijeđuje samo po majčinoj liniji.

Abstract (english)

Hair is one of the main characteristics of mammals. It grows from follicle located in dermis in three phases: anagen, catagen (growing phases) and telogen (resting phase), after which the hair falls off and the cycle repeats. This periodical shedding is one of the reasons why it is commonly found on crime scenes. It can also be pulled out in growing phase and then there is a big possibility that it contains a part of follicular tissue which is a rich source of DNA. Forensic analysis usually begins with macroscopic and microscopic analysis which is followed by DNA analysis. To be used as valid proof, hair must be properly collected at the scene and stored together with reference samples. Hair can be affected by many factors which is why it’s important for reference sample to be collected at the same time as the unknown one. Comparison microscope is used for comparison of two samples. It consists of two light microscopes connected by an optical bridge. Besides comparison, microscopic analysis can reveal information about area of hair growth, race and if it’s violently pulled out. However, DNA analysis is necessary in detecting age and gender and individualisation, which is possible if DNA can be extracted from follicular tissue or hair root. If the hair doesn’t have follicular tag or root, or there is not enough of extracted DNA (or it’s degraded), mtDNA can help with identification, but it can’t be used for individualisation since it is inherited only from mother’s side.

• Keywords: forenzika
• Language: croatian
• URN:NBN: urn:nbn:hr:217:307784
• Study programme: Title: Ecology; Study programme type: university; Study level: undergraduate; Academic / professional title: sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) biologije (sveučilišni/a prvostupnik/prvostupnica (baccalaureus/baccalaurea) biologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2020-09-09 12:11:14