生物信息学算法之Python实现|Rosalind刷题笔记：006 计算点突变数

汉明距离的定义：对于两条长度相等的字符串来说，汉明距离指的是它们之间不相同的字符数。对于两条 DNA，则是它们之间的点突变数目。

给定：两条长度相等的 DNA 序列（不超过 1kb）。

需得：计算汉明距离。

示例数据

GAGCCTACTAACGGGAT
CATCGTAATGACGGCCT

示例结果

7

Python 实现

Counting_Point_Mutations.py

import sys

def hamm(s1, s2):
    return sum([a != b for a, b in zip(s1, s2)])

def test():
    s1 = 'GAGCCTACTAACGGGAT'
    s2 = 'CATCGTAATGACGGCCT'
    return hamm(s1, s2) == 7

if __name__ == '__main__':
    if not test():
        print("hamm: Failed")
        sys.exit(1)

    lines = []
    with open('rosalind_hamm.txt') as fh:
        lines = fh.readlines()
    mutations = hamm(lines[0], lines[1])
    print(mutations)

汉明距离的计算：

1. zip()函数，将两条序列对应的元素打包成一个个元组；
2. 通过列表展开式判断对应元素是否不同；
3. sum()函数计算不相同的字符数，即为汉明距离。

Problem

Figure 1. The Hamming distance between these two strings is 7. Mismatched symbols are colored red.

Given two strings and of equal length, the Hamming distance between and , denoted , is the number of corresponding symbols that differ in and . See Figure 2.

Given: Two DNA strings and of equal length (not exceeding 1 kbp).

Return: The Hamming distance .

Sample Dataset

GAGCCTACTAACGGGAT
CATCGTAATGACGGCCT

Sample Output

7