'Whereas' as conjunction between main clause and subordinate clause?

Question

I am wondering if I can use 'whereas' as a conjunction between a main and a subordinate clause, with the subordinate clause following and giving a reason supporting the statement in the main clause. For example:

As a model system we consider a mutant zombie hoard, whereas the vast majority of zombie hoards fall into this category.

I realize that there is another use of 'whereas' to contrast two things; it's the third entry in the OED Online:

3. Introducing a statement of fact in contrast or opposition to that expressed by the principal clause: While on the contrary; the fact on the other hand being that. (The principal clause usually precedes, but sometimes follows as in 2.)

That's not what I mean. What I want is the second entry in the OED:

2. In view or consideration of the fact that; seeing that, considering that, forasmuch as, inasmuch as. (Chiefly, now only, introducing a preamble or recital in a legal or other formal document.)

However, in the OED, all of the examples for case '2' have 'whereas' at the beginning of the sentence, not in the middle. So, is it valid English to write "As a model system..." as above, or not?

Answer 1

There's nothing wrong with using whereas as a conjuction. The Cambridge Dictionaries Online site has a good example:

compared with the fact that; but:

In Los Angeles, a chief cause of this pollution is paved-road dust, whereas in San Diego, it's smoke from fireplaces.

The Oxford Advanced Learner's Dictionary offers a few more:

used to compare or contrast two facts

Some of the studies show positive results, whereas others do not.

We thought she was arrogant, whereas in fact she was just very shy.

However, in your particular sentence, the usage is quite strange. When used to separate two sentences, whereas should be use to compare the two statements, whereas in your sentence it's simply providing additional information. Since would make a lot more sense here:

As a model system we consider a mutant zombie hoard, since the vast majority of zombie hoards fall into this category.

Answer 2

My feeling is that the sense in which I've used 'whereas' is at the minimum "quite strange".

Firstly, it seems that many people are not even aware that 'whereas' can mean 'in consideration of the fact that', as evidenced by p.s.w.g.'s answer. Secondly, in the third case in the OED, I just noticed the comment:

(The principal clause usually precedes, but sometimes follows as in 2.)

This indicates to me that in case '2' (the sense in which I'm using the word), it's expected that the main clause follows the subordinate clause.