Department of Energy Argonne National Laboratory Office of Science NEWTON's Homepage NEWTON's Homepage
NEWTON, Ask A Scientist!
NEWTON Home Page NEWTON Teachers Visit Our Archives Ask A Question How To Ask A Question Question of the Week Our Expert Scientists Volunteer at NEWTON! Frequently Asked Questions Referencing NEWTON About NEWTON About Ask A Scientist Education At Argonne Interbreeding of Cats
Name: Jay
Status: Other
Grade:  Other
Location: N/A
Country: United States
Date: April 2005


Question:
How come a tiger and a lion can breed? How come a ligercannot breed?



Replies:
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 sterile.

vanhoeck


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.



Click here to return to the Molecular Biology Archives

NEWTON is an electronic community for Science, Math, and Computer Science K-12 Educators, sponsored and operated by Argonne National Laboratory's Educational Programs, Andrew Skipor, Ph.D., Head of Educational Programs.

For assistance with NEWTON contact a System Operator (help@newton.dep.anl.gov), or at Argonne's Educational Programs

NEWTON AND ASK A SCIENTIST
Educational Programs
Building 360
9700 S. Cass Ave.
Argonne, Illinois
60439-4845, USA
Update: June 2012
Weclome To Newton

Argonne National Laboratory