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Featuring information on Anne McCaffrey's Pern, including Dragonhealing, Herbalry, and Dracogenetics. |
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This text is compiled from factual, statistical, or other information originally from work done and/or owned by Anne McCaffrey. Credit is also given to Dr. Jack Cohen, who developed the theoretical basis for the McCaffrey-Cohen model. Statements expressed herein are ideas that may or may not coincide with those of Anne McCaffrey or Dr. Jack Cohen, and those ideas that have no readily available backing by either of the aforementioned are in no way to be interpreted as direct statements of the views, opinions, and/or statements made by the aforementioned.
Which came first, the dragon or the egg? Well, on Pern, we know the egg did. But how do the genes of the dragons control the proportions in the population? That is our goal: to discover the reasoning of Kitty Ping and her methods of allowing for the proportions we find in Pern today. There are two traits in dragons which go hand in hand: the deposition of trace amounts of gold in the hide and the apparent high rank of dragons with such metal deposition. The two dragons that express these traits in conjunction are golds and bronzes. (DLG p. 50, where the bronze hide was described as a "greeny gold." This would indicate some degree of gold deposition in the bronze hide, along with some other materials to create the bronze color.) This gene is a sex-linked recessive gene on the X chromosome, g. The pattern we would expect is: XgXg [Queen] and XgXY [Bronze] (listed as XgY for simplicity). This is not possible. If it were, the dragon population of Pern would be nothing but bronzes and queens. And imagine how much rivalry there would be then! So, deviating from Mendellian genetics (as does a lot of life on Earth, so this is permissible), a pattern of polygenic inheritance emerges, and the queen is now XGXg. Question: why? The answer lies in asking what these genes could possibly code for. Xg, which is common to both bronzes and queens, must code for a component required for gold deposition. Thus there are two sources for another component, either the XG allele or the Y chromosome. Both components must be present to produce a bronze or queen. Therefore:
Since the dragons of Pern are all the same species, the genomes must not be too different so as to make them all genetically incompatible. Based on the evidence available, There are two separate genes that affect draconic development among the autosomes (non-sex chromosomes). The first set of genes available have to do with development of higher ranking dragons, bronzes and queens. This, like the sex-linked gold metal genes, exist in two pieces, R and r, both of which must be present in conjunction with the gold deposition combinations [XGXg or XgY] to produce a high-ranking dragon. The inheritance patterns are:
Gold is only one component of dragon color. In the bronzes, for instance, there are more components that make an ordinarily gold hide bronze. Add to that the source of chemical green and blue for the other dragon shades, and the question of where these come from begins to arise. In the draconic physiology, copper is readily available--copper is an essential component for draconic blood cells as part of an oxygen-carrying accessory group, much like iron in mammalian red blood cells acts as part of hemoglobin. Green dragons would be considered jaundiced by mammalian standards, as the same component that makes ichor green would also make dragonhide green. It may be assumed that this oxygen carrying protein, or a derivative thereof, is used in the hide color. Blue dragons, however, are a completely different matter. The copper is in an ionic compound, copper sulfate, which appears as a very deep blue. The second component available for coloring dragonhide would be a pigment not unlike melanin or billirubin, both of which tend to be brown. When available exclusively in brown dragons or in a mixture with bronze dragons, the pigment contributes to the hide coloration.
NOTE: These pages were developed from an earlier work by an unknown author. If you are this author or you know who the author is, please email me at [email protected] and I will credit it correctly. All references to worlds and characters based on Anne McCaffrey's fiction are copyright© Anne McCaffrey 1967,2000, all rights reserved, and used by permission of the author. The Dragonriders of Pern® is registered U.S. Patent and Trademark Office, by Anne McCaffrey, used here with permission. Use or reproduction without a license is strictly prohibited.
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