Can gurus jump?

When I got in Tilly was doing her homework - about gurus. B said she should ask the question in the title - which was quite funny!
There was an interesting bit on the radio about how we are all related to the same people who were alive 3000 years ago. And if you do the maths it seems inevitable: the geometric sequence of ancestors - 2, 4, 8, 16 etc - if taken over 3000 years with, say, 4 generations per hundred years gives you a total number of ancestors of something like 1.3 times ten to the power of 36. That is most certainly more than the world's population was 3000 years ago! So we are all very distant cousins. And you never send me a Christmas card - you miserable bar stewards.