Introduction

During the course of a criminal investigation, many types of physical evidence are encountered as Sir Edmund Locard's principle (1930) also states that "whenever two objects come into contact, a transfer of material will occur. Trace evidence that is transferred can be used to associate objects, individuals, or locations" (Scientific Working Group on Materials Analysis, 1999). With the increasing rate of crime, identification of the person is the concern of the police and the identification is entirely based on fingerprints, hair samples, birth mark, eyes, voice etc. In all evidences, hair is one of the most common found evidence in majority of crime scenes. Human hair has been of interest to anthropologists, biologists and forensic scientists for establishing the identity or studying the variation. Human hair identifications are subjective interpretations of objective criteria. The variability and distribution of the microscopic characteristics are useful in determining whether or not a questioned hair could have originated from a particular individual.

It is recognized that hair comparisons do not constitute a basis for absolute personal identification. Whereas hairs cannot be positively identified as originating from a particular individual, it is unusual to find different people having the same hair characteristics.

In spite of processing like ageing, digestion and change in environment, hair is chemically most stable than any other biological sample. The microanatomy of the hair is characterized on its histological traits such as the cuticle, medulla, cortex, pigment granules, cortical fusi and others is important in the description of hair (Joshi et al., 2012). Hair analysis can indicate whether the source is human or animal, and also whether the source is a member of a particular race. It can determine if the hair has been dyed, cut in a certain way or pulled out, and where on the body it was located. In some cases, evidence of poisoning shows up in the hair. Vernon J. Gerberth, in Practical Homicide Investigation, points out that hair (and fiber) evidence is useful in helping to establish the scope of the crime scene, placing a perpetrator at a scene, connecting a suspect with a weapon, supporting witness statements, connecting crime scene areas (abduction, vehicle used, dump site). Many chemicals and biological substances that accumulate in hair can be detected and measured and makes hair samples good resource biomaterials in forensic science and physical anthropology (Chang et al., 2005).

Ever since the formulation by Huxley (1865) several anthropologist (Deniker 1900, Martin 1928, Hooton 1946, Koonz 1945, Garn 1948) have used morphological traits of hair for differentiation of human races. Interest in the microscopic aspects of hair was a relatively late phenomenon (Hausman 1925, Wynkoop 1929) and population variations in this world have not drawn much emphasis (Hrdy 1973, Das- Chaudhari & Chopra 1984). Marx (1906), metric and microscopic characters of humans have attracted the attention of forensic scientists, particularly due to its better chemical stability and resistance to decomposition as compared to other body tissues. It has been realized that hair evidence can provide useful clues to race, sex and site of the body. Das-Chaudhuri & Chopra (1983) have suggested the involvement of significant genetic component in the histo-morphological variables of human scalp hair thus highlighting their utility for studying population variations. Various histo-morphological hair parameters, such as medullation, hair index, medullary and scale count index have forensic applications for individualization (Chowduri 1963, Bhatis et al. 1971, 1976, 1980, Banerjee & Banerjee 1986) (Gaur et al., 2007). The present study was undertaken on two diverse population groups (Brahmins and Domars) of Uttar Pradesh, India in which 823 individual’s samples were collected for studying the range of variability that exists in terms of histomorphological characters of hair among population of Uttar Pradesh, India.