Sequence Conservation Analyses Often Use Computer-Based Alignment of the Nucleotide

question 15

Essay

Sequence conservation analyses often use computer-based alignment of the nucleotide sequences of equivalent genes in different organisms, or of the amino acid sequences of the corresponding proteins. The alignment below shows a BLAST alignment of the first 100 amino acids of the human CFTR (cystic fibrosis transmembrane receptor) protein (shown as the Query) and the equivalent sequence in the corresponding mouse protein (shown as Sbjct, an abbreviation of subject). The intervening middle line shows whether at the same position in the two sequences the amino acids are identical or chemically similar.
Query 1 MQRSPLEKASVVSKLFFSWTRPILRKGYRQRLELSDIYQIPSVDSADNLSEKLEREWDRE 60
MQ+SPLEKAS +SKLFFSWT PILRKGYR LELSDIYQ PS DSAD+LSEKLEREWDRE
Sbjct 1 MQKSPLEKASFISKLFFSWTTPILRKGYRHHLELSDIYQAPSADSADHLSEKLEREWDRE 60
Query 61 LASKKNPKLINALRRCFFWRFMFYGIFLYLGEVTKAVQPL 100
ASKKNP+LI+ALRRCFFWRF+FYGI LYLGEVTKAVQP+
Sbjct 61 QASKKNPQLIHALRRCFFWRFLFYGILLYLGEVTKAVQPV 100
Calculate (a) the degree of sequence identity for the aligned sequences (b) the degree of sequence similarity.

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Definitions:

MODE.MULT(data range)

A function in spreadsheet programs that returns an array of the most frequently occurring values in a given data range.

MODE.SNGL(data range)

A statistical function that returns the most frequently occurring value in a given data range.

Arithmetic Mean

The sum of a collection of numbers divided by the count of numbers in the collection, commonly known as the average.

Midrange

The statistical measure calculated by taking the average of the highest and lowest values in a data set.