MGP and BGP are matrix and bone gamma-carboxyglutamic acid proteins. BGP is osteocalcin.
"Origin and Evolution of BGP and MGP—It is quite clear that BGP and MGP have a common origin and that they are more closely related to each other than to any other VKD protein. This is well supported by the data base searching, the exon patterns, and protein sequence alignments showing that 1) BGP and MGP genes share the same simple gene organization and protein structure and 2) the C-terminal domain signature is similar in MGP and BGP. It is also clear that BGP and MGP are nearly if not completely absent in most non-vertebrate taxa. Levels of sequence similarity between BGP and MGP are much higher than one would expect to occur by convergence, suggesting that this gene group originated through gene duplication followed by subsequent sequence divergence. This duplication (gene, chromosome, or genome duplication) probably occurred very early in vertebrate evolution, being almost certainly an ancient event. Strong evidence for whole genome duplication has been shown for vertebrates (57). After the divergence of the cephalochordates from the chordate line, a genomic duplication occurred before jawless fish evolved around 500 Myr ago (Fig. 7). Another genomic duplication event probably led to the evolution of jawed fish around 400 Myr ago (Fig. 7). These two duplications led to the development of many distinctive vertebrate features, such as cartilage and bone. We hypothesize that the first genome duplication (before the branching of jawless fish) originated the ancestor gene of MGP, and the second genome duplication (before the branching of cartilaginous fish) would have produced the BGP ancestor gene. The BGP (380 Myr ago) and MGP (480 Myr ago) emergence times estimated from the evolutionary rate agree well with this conjecture. The appearance of MGP would be followed by cartilage formation and that of BGP by bone formation. After duplication, gene duplicates (BGP in this case) often experience relaxed evolutionary constraints. This promotes functional diversification of duplicates and biochemical innovation through mutations and recombination. In other words, duplicates evolve to acquire new functions. Several more speculative lines of evidence for BGP being a duplicate of MGP have been collected: 1) the presence of a MGP-like immunoreactive protein has been observed in lamprey (the more ancient species tested), whereas BGP was not detected7; 2) MGP is associated with cartilage, which appeared with the first vertebrates, whereas BGP is only associated with bone, a structure that appeared later in evolution; and 3) BGP seems to be better conserved than MGP."
The precursor to MGP did not have the same function that MGP has and unfortunately has been lost forever. Interestingly, the fruit fly protein Msp-300 (muscle-specific protein 300) C-terminus has some homology to well-conserved (and therefore required for function) regions of MGP. Msp-300 and MGP may have had a common origin in a gene existing prior to the evolution of the vertebrates.
http://www.jbc.org/cgi/content/abstract/280/29/26659
"Evolution of Matrix and Bone g-Carboxyglutamic Acid Proteins in Vertebrates." Vincent Laizé, Paulo Martel, Carla S. B. Viegas, Paul A. Price, and M. Leonor Cancela. Journal of Biological Chemistry, 2005, 289, 26659-26668.
"However, this one can be traced back quite far enough to cause any young earth creationist great discomfort."
I don't think so......i'm sure not feeling any discomfort by all this rambling by evolutionary biologists.
Did you know the odds are 10(161) to 1 that not one usable protein would have been produced by chance in ALL THE HISTORY of the earth. Note this is a figure containing 161 zeroes. It might be well to recall that even if one molecule were obtained, it would not help at all in arranging the second protein molecule unless there existed an accurate duplication process. Even if there were such a process, there are many other kinds of proteins needed before there can be a living organism. Did you know that in a minimal cell, the 239 protein molecules required include at least 124 different protein species.
So all your neat little hypotheticals are not based on facts just philosophical meanderings.
The probablility of forming one protein molecule by chance is one 10 to the 243rd power..that is a figure of 1 followed by 243 zeros. A fraction so small that one may say the probability is zero.