<div>Background: Nattukuttai is a small-sized cattle population, native to north-eastern districts of Tamil Nadu. In light of the ongoing research on genetic characterisation of cattle genetic resources of India, the present study was undertaken with the objective of cytogenetic characterisation of Nattukuttai cattle, which is imperative for its conservation and genetic implications to breeding programs. 
 
Methods: Blood samples from ten Nattukuttai cattle (five males and five females) were utilized to study the chromosome profile through short-term lymphocyte culture method. Good metaphase spreads were selected for estimation of the relative length, arm ratio, centromeric index and morphological index. 
 
Result: The diploid number was 60. All the 29 pairs of autosomes and Y-chromosome were acrocentric while X-chromosome was sub-metacentric. The mean relative length of autosomes ranged from 5.24 &plusmn;0.08 to 1.90&plusmn;0.06. X-chromosome was the largest in the karyotype (5.64&plusmn;0.12), while the Y-chromosome was the smallest (1.85&plusmn;0.03). The arm ratio, centromeric index and morphological index were 1.98&plusmn;0.02, 0.33&plusmn;0.03 and 4.06&plusmn;0.4 respectively. The study revealed that the chromosome architecture of Nattukuttai cattle was similar to that of other breeds of Zebu cattle.</div>

Cytogenetic Characterisation of Nattukuttai - A Non-descript Cattle Population of Tamil Nadu