I don't really know either - it was really just a part of a joke about the red-head thing And about being the recipient of an unusual genetic gift - less than 2% are so endowed, and within that number there are more than forty different variants.

(As a eighteen year old or thereabouts, together with a couple of friends, I tried to ditch attending a seminar - 'Black, White and Khaki' - that the entire student population of the community college was expected to sit through. We were discovered and ushered into the assembly hall, where the seats had all been taken, save for three right in the very center of the first row. After delivering his talk, the presenter asked if there were any questions and, as he hadn't mentioned we of the carrot-topped persuasion, I raised my hand to ask about gingers... and was then treated to a very detailed twenty minute explanation of why and in what ways I and my people were genetic mutations as I shrank lower and lower in my seat, feeling on the back of my head the searing gaze of every single one of the hundreds of eyeballs all looking at me. Did I feel special!)

Less chromosome 16 = more grams in body fat?

That's tough. I know nothing about gene pathology and gene chemistry. I guess for starters, we can say that the different possible combinations of A,C,T,and G, with at least one nucleotide forms irreducible compounds with irreducible properties. However, I don't have a single clue where to look up this information.

As for chromosome 16, it appears to be a very sensitive chromosome. Just look here:

[ghr.nlm.nih.gov]