Sequence scanning chicken cosmids: a methodology for genome screening

The chicken genome is relatively poorly studied at the molecular level. The karyotype 2n=78 is divided into three main chromosomal sub-groups: the mac rochromosomes (six pairs), the intermediate microchromosomes (four pairs) a nd the microchromosomes (29 pairs). Whilst the microchromosome group compri se only 25% of the DNA, increasing evidence is proving that this is disprop ortionate to their gene content. This paper demonstrates the utility of cos mid sequence scanning as a potential method for analysing the chicken genom e, providing an economical method for the production of a molecular map. Th e GC content, gene density and repeat distribution are analysed relative to chromosomal origin. Results indicate that gene density is higher on the mi crochromosomes. During the scanning process an example of conserved linkage between chicken and human (12q34.2) has been demonstrated. (C) 1999 Elsevi er Science B.V. All rights reserved.