Molecular cytogenetic analysis of the chicken and red-legged partridge chromosome 4 repatterning

Conserved genome homologies between the chicken and partridge have been dem onstrated for chromosomes 1 and Z in previous studies. Morphological differ ences between the chicken and partridge for chromosome 4 have also been ide ntified. The chicken chromosome 4 is submetacentric while the partridge chr omosome 4 is acrocentric. We now report that in spite of this morphological difference, both species share extensive homology for chromosome 4 as dete rmined by fluorescent in situ hybridization (FISH). Since only two chromoso mes of the partridge karyotype showed FISH signals, our observation suggest s that a chromosome rearrangement (peri- or paracentric inversion) has occu rred in the partridge chromosome 4.