X-STR ANALİZİNİN ADLİ BİLİMLERDEKİ ÖNEMİ

Öz

Adli bilimlerde olay yerinden toplanan biyolojik bulgular, suçu aydınlatma ve suçluyu tespit etmede büyük öneme sahiptir. Biyolojik bulguları incelemede en önemli yöntem DNA analizidir. Olay yerinden alınan biyolojik bulgular ve şüpheli şahıstan alınan biyolojik numuneler DNA analiziyle kıyaslanır. Ayrıca akrabalık testi de bu yöntemle yapılmaktadır. Biyolojik örneklerden analiz; DNA izolasyonu, PCR ve elektroforez işlemleriyle gerçekleştirilir. DNA molekülünün tümü protein üretiminden sorumlu değildir. Protein kodlayan kısım tüm genomun %3’ü kadardır. Protein kodlamayan kısım ise tekrarlardan oluşmaktadır. Yapısal olmayan DNA bölgelerinde, özellikle farklı uzunluklarda nükleotid dizilerinin değişik sayıda ard arda tekrarlanmasıyla oluşan diziler satellit olarak adlandırılır. Bunların en kısa olanına mikrosatellit STR=Short Tandem Repeat adı verilir. Bu diziler yüksek oranda polimorfizm gösterir. Adli uygulamalarda uzun süre sadece otozomal STR’ler kullanılmış ve bu incelemelerin yeterli olmaması nedeniyle Y-STR ve mitokondriyal DNA da incelemelere dahil edilmiştir. Son zamanlarda kullanım alanına girmekte olan X-STR analizleri daha karmaşık akrabalık olaylarının çözümlenmesine imkan vermektedir. Çocuğun kız olması koşuluyla; özellikle babanın bulunamadığı durumlarda babaanne-kız torun arasında X-STR analizleri ile babalık davaları çözümlenebilir. Ayrıca, akraba iki erkeğin baba adayı olduğu durumlarda ve iki kız çocuğunun, aynı babadan olup olmadığının araştırılması gibi durumlarda X-STR’ler kullanılabilir. Aynı zamanda, ensest vakalarda ve abortus materyalinin incelenmesinde çok güçlü bir yöntemdir.

Anahtar Kelimeler

• X-STR
• polimorfizm
• adli kimliklendirme
• babalık testi
• adli biyolojit

IMPORTANCE OF X-STR ANALYSIS IN FORENSIC SCIENCE

Öz

In forensic sciences, biological findings gathered from crime scene is quite important to illuminate the crime as well as determining the criminal. The most important examination method of biological evidence is DNA analysis. Biological evidence collected from the crime scene and biological samples taken from suspicious persons are compared with DNA analysis. In addition, kinship tests are also done with this method. Analysis in biological samples is carried out by DNA isolation, PCR and electrophoresis. All of the DNA molecule is not responsible for protein production. Proteincoding part, is about 3% of the entire genome. Non protein-coding part consists of duplication. In non-structural DNA regions, sequences which are especially produced by the repetition of different numbers of nucleotide sequences in different lengths and which are called as satellites. The shortest one of these is called as microsatellite STR = Short Tandem Repeat . These sequences show polymorphism in high rates. In forensic applications, only autosomal STR had been used for long time. Since this examination is not sufficient, Y-STR and mitochondrial DNA examinations have been included. X-STR analysis that is recently used, provides solutions to much more complicated kinship cases. Provided that child is a girl; paternity cases in which particularly the father cannot be reached may be resolved with X-STR analysis between paternal grandmother and granddaughter. In addition, X-STR can be used in such investigation cases where there are two relative father candidate as well as examination whether or not two girl childreen have the same father. Also, it’s a very strong method in incest cases and investigation of abortion material.

Anahtar Kelimeler

• X-chromosome STR
• polymorphism
• forensic identification
• paternity testing
• forensic biology

Kaynakça

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