Hereford bull calf (IMAGE) Whitehead Institute for Biomedical Research Caption Researchers at Whitehead Institute have sequenced the Y chromosome of a Hereford bull. Credit Richard Webb / Hereford bull calf / CC BY-SA 2.0 Usage Restrictions Credit must be given License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.