Calculating autosomal admixture from uniparental markers

If a population is 50% black on their paternal side (Y-DNA) and 50% white on their maternal side (mtDNA), will the autosomal loci of that population reflect both of those ancestries equally (50/50), seeing as how autosomal loci are biparentally inherited? Or is it possible that because of autosomal recombination, both paternal and maternal genetic contributions will be skewed so that the combined autosomal loci of the population will reflect 20% black and 80% white ancestry?

Please back up your answer with hard evidence gleaned from scientific papers.

Another way of expressing my question is, does Y-DNA + mtDNA = x/2 = autosomal DNA, assuming that we inherit 50% of our genes maternally and another 50% paternally? or does recombination affect how maternal and paternal admixture in a population is expressed? Please explain why.

Merged post follows:

In a nutshell, should estimates of admixture based on mtDNA and Y-DNA be expected to agree with estimates of admixture based on autosomal DNA? Why or why not?