Pop Genetics of Releases

Paul Cherubini paulcher at concentric.net
Thu Sep 23 20:07:28 EDT 1999

Anne Kilmer wrote (in response to Jacob Groth):

> Enormous genetic disruptions [of Monarchs] are taking place [because of 
> releases] and you tell me that it is harmless because it is happening and because it 
> "delights children".

Anne, the information below was copied from the Monarch Watch's website:

                              DNA Variation in Monarch Butterflies

Brower, A.V.Z. and T.M. Boyce. 1991. Mitochondrial DNA variation in
Monarch butterflies. Evolution 45(5): 1281-1286 

Andy Brower and Thomas Boyce studied the mitochondrial DNA (mtDNA) of
Monarch butterflies from the United States, Mexico, and the West Indies
to see how similar or different their genetic material was. 

They were especially curious about whether the eastern and western
populations of Monarchs in North America were genetically different; the
eastern population overwinters in Mexico while the western one
overwinters in California, and there is no evidence that these two
populations ever interbreed. 

They looked at variation in mtDNA using restriction enzymes, a technique
that identifies differences in DNA sequences. If one population, or
individual, had a small change in its DNA, this technique can reveal
that change. In some other insect species, studies have found that there
are big differences in individuals' mtDNA between regional populations,
and sometimes even within a region.

To their surprise, Brower and Boyce found almost no variation in any of
the Monarch populations' mtDNA, including the ones from the WestIndies.
Using 13 restriction enzymes, they found only two individuals with a
single difference in one site, and they attribute this difference to a
single base substitution. 

This level of similarity in the DNA from geographically isolated
populations is dramatically different from most other studied groups of

Vertebrates, for example, have differences at 10 times this level while
other insects show differences in mtDNA even within a population.

Paul Cherubini, Placerville, California

More information about the Leps-l mailing list