أنت تسأل وDarwin يجيب .

Thousands of new species are discovered yearly, and new DNA and protein sequences are determined daily from previously unexamined species (Wilson 1992, Ch. 8). At the current rate, which is increasing exponentially, over 20,000 new sequences are deposited at GenBank every day, amounting to over 34 million new bases sequenced every day. Each and every one is a test of the theory of common descent. When I first wrote these words in 1999, the rate was less than one tenth what it is today (in 2004), and we now have 20 times the amount of DNA sequenced.

Based solely on the theory of common descent and the genetics of known organisms, we strongly predict that we will never find any modern species from known phyla on this Earth with a foreign, non-nucleic acid genetic material. We also make the strong prediction that all newly discovered species that belong to the known phyla will use the "standard genetic code" or a close derivative thereof. For example, according to the theory, none of the thousands of new and previously unknown insects that are constantly being discovered in the Brazilian rainforest will have non-nucleic acid genomes. Nor will these yet undiscovered species of insects have genetic codes which are not close derivatives of the standard genetic code. In the absence of the theory of common descent, it is quite possible that every species could have a very different genetic code, specific to it only, since there are 1.4 x 1070 informationally equivalent genetic codes, all of which use the same codons and amino acids as the standard genetic code (Yockey 1992). This possibility could be extremely useful for organisms, as it would preclude interspecific viral infections. However, this has not been observed, and the theory of common descent effectively prohibits such an observation.

As another example, nine new lemur and two marmoset species (all primates) were discovered in the forests of Madagascar and Brazil in 2000 (Groves 2000; Rasoloarison et al. 2000; Thalmann and Geissmann 2000). Ten new monkey species have been discovered in Brazil alone since 1990 (Van Roosmalen et al. 2000). Nothing in biology prevents these various species from having a hitherto unknown genetic material or a previously unused genetic code—nothing, that is, except for the theory of common descent. However, we now know definitively that the new lemurs use DNA with the standard genetic code (Yoder et al. 2000); the marmosets have yet to be tested.

Furthermore, each species could use a different polymer for catalysis. The polymers that are used could still be chemically identical yet have different chiralities in different species. There are thousands of thermodynamically equivalent glycolysis pathways (even using the same ten reaction steps but in different orders), so it is possible that every species could have its own specific glycolysis pathway, tailored to its own unique needs. The same reasoning applies to other core metabolic pathways, such as the citric acid cycle and oxidative phosphorylation.

Finally, many molecules besides ATP could serve equally well as the common currency for energy in various species (CTP, TTP, UTP, ITP, or any ATP-like molecule with one of the 293 known amino acids or one of the dozens of other bases replacing the adenosine moiety immediately come to mind). Discovering any new animals or plants that contained any of the anomalous examples proffered above would be potential falsifications of common ancestry, but they have not been found