First report of GTG-banded nomenclature of Pakistani Lohi sheep (Ovis aries)

Th e present study was planned to generate the G-band nomenclature of the commonly occurring Lohi sheep breed in the Punjab province of Pakistan. Whole blood samples were collected through jugular venepuncture in heparinised vacutainers. Th e metaphase slides were prepared using standard protocols. Th e results from microscopic screening of 50 good quality metaphase cells from each animal were studied and they revealed a chromosome complement of 54, XX and XY in Lohi sheep. Th e fi rst 3 pairs were sub/metacentric whereas the other autosomes, including X, were classed as acro/subacrocentric. Th e Y chromosome was the smallest metacentric chromosome and had a starlike presentation. Th e trypsinisation time for optimal G-bands was highly variable, and individual chromosomes were identifi ed by G-positive and negative band markers. Th e identifi cation of chromosomes 4 & 6, 8 & 9, and 19-26 was diffi cult because these chromosomes were indistinct and small. Th e X chromosome was the largest sub/acrocentric, with a prominent G-positive band along the lower middle length. Complete G-band homology was noticed between Lohi and other reported sheep breeds from diff erent parts of the world. Th e G-band ideogram of Lohi was also constructed based upon the G-band organisation observed in the Lohi genome. None of the 350 metaphase cells studied revealed chromosomal abnormalities.