There are about 4 x 10^° possible combinations 

 of the 26 naturally occurring amino acids. Ad- 

 ditional compounds allow combinations far in 

 excess of the number of known or anticipated 

 species. 



From the preceding resume 1 of the litera- 

 ture, it appears that closely related members 

 of a genus can be distinguished on the basis of 

 their chromatographic patterns. That is to say, 

 the biochemical data tend to be consistent with 

 the morphological data and with some genetic 

 data. However, before the results of this tech- 

 nique can be used as prima facia evidence for 

 speciation, the limits of individual variation 

 will have to be determined. 



Ross, Holtman, and Gilfillin (1955) have 

 shown that a bacterial infection in chicks mat- 

 erially reduces the amounts of four amino acids 

 in blood and liver tissue. The variation im- 

 posed by diet and age has been demonstrated. 

 Other sources of organismal variability, such 

 as sex, and environmental variability, such as 

 temperature, should be evaluated. 



As with classical systematics, the in- 

 vestigator will have to know something of the 

 intra -generic biochemical variation before he 

 can make any statements about the significance 

 of intra -specific variation. Although many of 

 the same difficulties met at the specific level 

 will be encountered at the sub-level, the magni- 

 tude of variability will be reduced and therefore 

 harder to assess. Differences between species 

 are usually so great that they can be recognized 

 at the morphological level, but the more subtle 

 changes in the genome associated with sub- 

 species may be hidden. The resolving power of 

 chromatography at these low levels of variation 

 may prove to be most useful in the separation 

 of such populations . Just as morphology has 

 been useful for the study of speciation, compar- 

 ative biochemistry may become a powerful tool 

 for investigation of subspeciation. 



REFERENCES 



Ball, Gordon H., and Edward W. ClarK 



1953. Species differences in amino acids 

 of culex mosquitoes. Systematic 

 Zool., 2(3): 138-41. 



Block, Richard, Emmett L. Durrum, and 

 Gunter Zweig 

 1955. A manual of paper chromatography 

 and electrophoresis . Acad. 

 Press, Inc. N. Y. 



Buzzati -Traverso, Adriano A. 



1953. Paper chromatographic patterns 

 of genetically different tissue: a 

 contribution to the biochemical 

 study of individuality . Proc . Nat. 

 Acad. Sci., 39:376. 



Buzzati-Traverso, A. A., and Andreas B. 

 Rechnitzer 

 1953. Paper partition chromatography in 

 taxonomic studies. Science, 117, 

 (3029):58-9. 



Clark, Edgar W . , and Gordon H . Ball 



1951 . The free amino acid in the whole 

 bodies of culicid mosquitoes. 

 Jour. Parasitol., 37, (5) Sec. 2: 29. 



1952. 



Consden, 

 1944. 



The free amino acids in the whole 

 bodies of culicid mosquitoes. 

 Exptl. Parasitol., 1, (4):339-46. 



, A.H. Gorden, and A. P. Martin 

 Qualitative analysis of proteins: 

 a partition chromatographic method 

 usingpaper. Biochem.J., 38:224- 

 232. 



Cramer, Fredrick 



1953. Papierchromatographie . Verlag 

 Chemie GMBH. Weinheim/ 

 Bergstra . 



Dannevig, E.N. 



1955. Differentiation of varieties and 

 species of marine fish with the 

 help of chromatographic separation . 

 Tideskrift for Mermetikdustri 

 41(3):121-123. 



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