There's so much DNA in common we have with the other apes that this in itself is evidence of common ancestry. This includes genetic relics such as the broken vitamin c gene we share with other primates and the thousands of shared retroviral inserts that are basically junk but are clearly shared. These discoveries make the case for common descent among the apes and other mammals proven as strong as the DNA evidence courts use to determine paternity.
And it is still possible for a mutation to, at times, be beneficial.
What you are describing is anecdotal, familiar to anyone marginally well read on the subject and hardly conclusive. Equivocating the GULO gene with using DNA to identify an individual is gross hyperbole. The obvious problem is that if things in common, like mutations at mutational hot spots, has an inverse logic Darwinians refuse to admit. If things in common are proof of common ancestry then is the inverse logic intuitively obvious? The ERVs are a prime example of this kind of homology argument gone wrong. When Talk Origins made it's probability argument on identical sequences involving mutations ERVs were thought to be 1% of the human genome, they are now known to be 8% and what even more important:
With more than 100 members, CERV 1/PTERV1 is one of the most abundant families of endogenous retroviruses in the chimpanzee genome. (Gen. Bio. 2006)
These are ERVs that exist in Chimpanzee genomes but are completely absent in Human genomes.
Against this background, it was surprising to find that the chimpanzee genome has two active retroviral elements (PtERV1 and PtERV2) that are unlike any older elements in either genome...PtERV1-like elements are present in the rhesus monkey, olive baboon and African great apes but not in human, orang-utan or gibbon, suggesting separate germline invasions in these species. (Nature 2005)
The inverse logic is intuitively obvious, if DNA is such a compelling evidentcial argument then why is it that this causes to confusion for Darwinians:
The 118-bp HAR1 region showed the most dramatically accelerated change (FDR-adjusted P , 0.0005), with an estimated 18 substi- tutions in the human lineage since the human–chimpanzee ancestor, compared with the expected 0.27 substitutions on the basis of the slow rate of change in this region in other amniotes (Supplementary Notes S3). Only two bases (out of 118) are changed between chimpanzee and chicken, indicating that the region was present and functional in our ancestor at least 310 million years (Myr) ago.(An RNA gene expressed during cortical development evolved rapidly in humans, Nature)
For 300 million years only 2 substitutions allowed, then suddenly about 2 mya 18 suddenly happen. This isn't an isolated incident all protein coding genes on average have one amino acid substitution per lineage per gene, only 29% are actually identical. The smoking gun for me are the indels, if they are no problem then why do evolutionists avoid the subject of indels and mutation rates like the plague?
Genetics is the single strongest challenge to the myth of the stone age ape man. Just chanting natural selection doesn't work when you start looking at mulitplicative effects on fitness and synergistic epistasis. Brain related genes do not respond well to mutations and the only other explanation would be a molecular mechanism that can rewrite these highly conserved genes and none is known to exist.
Have a nice day
Mark