Two @entity1 gene families display preferences for different XXXX and have distinct codon usage patterns.

@entity1 @entity2036 @entity219 @entity377 @entity1129 @entity4050
Analysis of base composition has proven important for functional gene analysis. By comparing base composition and codon usage between two specific @entity1 gene families we were able to show a highly conserved @entity377 distribution among the members of one gene family and a significant difference between the two families. The two groups selected for analysis were the @entity1 @entity4050 gene family, which represents six secreted @entity1 plasma proteins with functions in immune defense, and a class of four @entity1 @entity219 finger proteins, termed early growth response (EGR) proteins, which represent DNA-binding transcription factors. The @entity377 distribution of each gene family is distinct: members of the @entity4050 gene family represent @entity1129 -rich genes, displaying an overall @entity1129 @entity377 content of 62.8% and a particular preference for A @entity2036 (33.9%). In contrast, the EGR genes are GC-rich (55.9%) and C @entity2036 are used in 31.2%. This @entity377 difference affects codon usage among synonymous codons and is considered of biological significance, as it affects DNA stability. The codon preference is particularly high at codon position 3, where each family selects for codons which have the preferred @entity377 at this silent third position. At position 3, A @entity2036 are preferred by @entity4050 genes in 36.3% of the 2, 503 codons analyzed, compared to 10% of the 1,876 codons analyzed for the EGR family. In contrast, C @entity2036 are used by the EGR family in 48.1%, compared to 16% of the triplets used by the @entity4050 gene family. This comparison of two @entity1 gene families shows that @entity377 distribution and codon usage is not uniform within the @entity1 organism and the described differences most likely represent selection constraints between the polymorphic @entity4050 and highly conserved EGR genes.
