Base pairs classification

Among the many findings of the HGP is that all humans are 99.9% identical at the level of DNA. Consequently, any two humans on the planet are likely to vary genetically only once in every one thousand base pairs. This finding reconfirms that the species Homo sapiens is relatively young (about 100,000 years old) and that there are no subspecies. Thus there is no scientific basis for racial classifications race is a purely social construct. 

With few exceptions, all the promoter regions contain the consensus sequence TTTA /tA. There are some indications that minor variations in this sequence motif occur in different orders of the hyperthermophiles but it is difficult to assess how significant this is given the relatively small number of sequences available. This is complicated further by recent analyses of the phylogeny of the hyperthermophiles based on partial 23 S rRNA sequences [40] which suggest that the taxonomic classification in Table 1 needs revision (see section 7). For many promoters the A-T-rich motif is longer than 5-6 base pairs indeed, for the Mt. fervidus genes it extends to 14-15 consecutive A-T pairs (Table 4). 

One approach that has been explored is the use of genetic markers to define race. Given that there are three billion bases in human DNA with 99.9% of these bases exactly the same across individuals, this means that each individual has more than three million unique base pairs. There are too many unique base pairs per individual for classification using all unique base pairs. Hence, the base... 

Table 7.2 Classification of acid-base pairs in aqueous solution according to their acidic strength.

The preceding strategy for the construction of decision trees provides an efficient way for inducing compact classification decision trees from a set of (x, y) pairs (Moret, 1982 Utgoff, 1988 Goodman and Smyth, 1990). Furthermore, tests based on the values of irrelevant variables are not likely to be present in the final decision tree. Thus, the problem dimensionality is automatically reduced to a subset of decision variables that convey critical information and influence decisively the system performance. 

In retrospect, it was a consistent and logical step for Seebach and Prelog to propose, in 1982 2 a reactant-based descriptor system (SP system) corresponding to the Izumi -Tai classification. The SP system makes use of the familiar Re Si system already discussed (see Section 1.1.2.2.). Again, relative configurational relationships must be incorporated, something which the SP system does by straightforward combination of descriptors into Ikjul pairs (relative topicities) (see Section 1.1.2.2. and 1.1.4.). 

This classification is summarized by element in Fig. 2.3. Its value lies in the generalization that soft acids interact more strongly with (i.e., accept electron pairs more readily from) soft bases, whereas hard acids bond more... 

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