An experiment was conducted to study the effects of substitution soybean meal (SBM) with canola meal (CM) and formulated diets based on total and digestible amino acid on performance, egg quality, organs weight and blood parameters of laying hens from 73 to 83 weeks of age. A total of 128 laying hens were distributed by completely randomized design in a 2×2 factorial arrangement with 2 protein ...

Evolutionary models measure the probability of amino acid substitutions occurring over different evolutionary distances. We examine various evolutionary models based on empirically derived amino acid substitution matrices. The models are constructed using the PAM and BLOSUM amino acid substitution matrices. We rescale these matrices by raising them to powers to model substitution patterns that ...

Natural selection operating on amino acid substitution at single amino acid sites can be detected by comparing the rates of synonymous (r(S)) and nonsynonymous (r(N)) nucleotide substitution at single codon sites. Amino acid substitutions can be classified as conservative or radical according to whether they retain the properties of the substituted amino acid. Here methods for comparing the rat...

This paper introduces a method for identifying empirically conserved amino acid substitution groups. In contrast with existing approaches that view amino acid substitution as a pairwise phenomenon, the method presented here identifies conserved groups of amino acids using a data structure called a conditional distribution matrix. The conditional distribution matrix extends the concept of a pair...

MOTIVATION We address the question of whether there exists an effective evolutionary model of amino-acid substitution that forms a metric-distance function. There is always a trade-off between speed and sensitivity among competing computational methods of determining sequence homology. A metric model of evolution is a prerequisite for the development of an entire class of fast sequence analysis...

Models of amino acid substitution present challenges beyond those often faced with the analysis of DNA sequences. The alignments of amino acid sequences are often small, whereas the number of parameters to be estimated is potentially large when compared with the number of free parameters for nucleotide substitution models. Most approaches to the analysis of amino acid alignments have focused on...

So I’ve just suggested that the neutral theory of molecular evolution explains quite a bit, but it also ignores quite a bit. The derivations we did assumed that all substitutions are equally likely to occur, because they are selectively neutral. That isn’t plausible. We need look no further than sickle cell anemia to see an example of a protein polymorphism in which a single amino acid differen...

So I’ve just suggested that the neutral theory of molecular evolution explains quite a bit, but it also ignores quite a bit. The derivations we did assumed that all substitutions are equally likely to occur, because they are selectively neutral. That isn’t plausible. We need look no further than sickle cell anemia to see an example of a protein polymorphism in which a single amino acid differen...

Methods for alignment of protein sequences typically measure similarity by using a substitution matrix with scores for all possible exchanges of one amino acid with another. The most widely used matrices are based on the Dayhoff model of evolutionary rates. Using a different approach, we have derived substitution matrices from about 2000 blocks of aligned sequence segments characterizing more t...