New Robertsonian translocation chromosomes in domestic sheep (Ovis aries).

We report two new Robertsonian centric fusions, designated t4 and t5, in New Zealand Romney sheep. Q- and G-banding studies show that sheep chromosomes 5 and 8 are fused in t4 and that chromosomes 8 and 22 are fused in t5. The presence of large blocks of centromeric heterochromatin in t4 and t5 suggests that the fusions may be of recent origin.