Interbreeding of Cats
Country: United States
Date: April 2005
How come a tiger and a lion can breed? How come a ligercannot
Tigers and lions can create hybrid offspring but usually hybrids cannot
breed because their chromosome numbers are uneven.
For example, horses and donkeys can breed to produce the hybrid called a
mule. Horses have 62 chromosomes and donkeys have 64 (or the other way
around-I forget!). Their mule offspring have 63 chromosomes, an uneven
number. So if two mules tried to have babies, the chromosomes wouldn't line
up together at meiosis when creating eggs or sperm. So hybrids are usually
If lions and tigers do not carry the same genes on the same chromosomes
(which is only possible if they contain the same number of chromosomes and I
don't whether they do or not but you can find out by doing a search on
Google), then when the liger sex cells undergo meiosis, the probability that
the right complement of chromosomes would end up in the sperm or egg would
be approximately 2 in a million (2 to the 20th power times 2) assuming they
have 20 pairs of chromosomes. In other words the sperm or egg must contain
20 tiger chromsomes or 20 lion chromosomes and it is a 50-50 probability as
to whether a sperm of egg cell receives the tiger chromosome or the lion
chromosome during meiosis.
Ron Baker, Ph.D.
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Update: June 2012