Chile

Cielo Estrellado please please do not support Al Andalus on this. The word Mestizo is never used in the hispanic world to describe people who are predominantly European as is the case for most Chileans. 

Firstly, as you may know, in Latin America it is used for those who are predominantly amerindian in their ancestry. (It would apply in Mexico and Central America). 
Secondly, there is no defined ethnic group in Chile which can be defined as mestizo, there are just people with more or less Indian bood, Spanish origin being nearly always the larger part of the ancestry. There is no sense of common belonging shared exclusively by people with amerindian ancestry which excludes people who dont have this ancestry. This is a vital characteristic of an ethnic group.
The word mestizo is pejorative in our language and should be used as little as possible. Ill give you an example. When the movie "Harry Potter and the half-blood prince" came out in the Spanish speaking world, it was translated into Harry Potter and the Prince, because of the negative connotations that the word mestizo implied.
Finally, in our cultural community, Latinness, Spanishness (or if you want to use racial terms "whiteness") is an expansive concept which does not exclude people placind then in a different ethnic group on the basis of their blood being "tainted" as happens in the Anglo Saxon world. Although, I agree that that in certain countries where racial divisions have been stronger due to a much larger Amerindian community, (such as Peru or Guatemala) leading to implications regarding identity and ethnicity..

Anyways I hope you understand my position and we can establish some dialogue on this issue which transcends the narrow (and in my opinion racist) perspective of Genetic studies.
I also hope you are not a sock puppet of user: al andalus! This would make things much harder:-)