Just chiming in to agree and expand: if you're attempting to use molecular clock assumptions, you're sampling a survivor descended from many generations of reproductive winners - that doesn't tell you how many gamete-killing or zygote-killing mutations happened along the way.
Interestingly, I just read that some regions of that "junk" DNA are so highly conserved that mutations there are highly likely to be lethals:
http://biology.plosjournals.org/perlserv/?request=get-document&doi=10.1371%2Fjournal.pbio.0030007Executive summary: authors found more than a thousand short-ish (over 100 base-pairs) non-coding sequences strongly conserved between the human and puffer fish genomes.
cheers,
JMJ