Having been identified with RBA-Banding technique, Y chromosome of Xizhen showed no short arm, so it belonged to telueentric chromosome, but other three breeds had acrocentric Y chromosomes.

• 经RBA带鉴别,西镇牛丫染色体无短臂,为端着丝点染色体,其余3个品种为近端着丝点丫染色体。