All Y chromosomes in existence today are descended from a single ancestor's who is thought to have lived about 140,000 years ago.

• Aa single ancestor's who is thought to have lived  
• Ba single ancestor's who was thought to live  
• Ca single ancestor whom it is thought had lived  
• Dthe Y chromosome of a single ancestor who is thought to have lived  
• Ethe Y chromosome of a single ancestor whom it was thought had lived