Task: Bioinformatics_Sequence mutation


C++: #include <array>
#include <iomanip>
#include <iostream>
#include <random>
#include <string>

class sequence_generator {
public:
    sequence_generator();
    std::string generate_sequence(size_t length);
    void mutate_sequence(std::string&);
    static void print_sequence(std::ostream&, const std::string&);
    enum class operation { change, erase, insert };
    void set_weight(operation, unsigned int);
private:
    char get_random_base() {
        return bases_[base_dist_(engine_)];
    }
    operation get_random_operation();
    static const std::array<char, 4> bases_;
    std::mt19937 engine_;
    std::uniform_int_distribution<size_t> base_dist_;
    std::array<unsigned int, 3> operation_weight_;
    unsigned int total_weight_;
};

const std::array<char, 4> sequence_generator::bases_{ 'A', 'C', 'G', 'T' };

sequence_generator::sequence_generator() : engine_(std::random_device()()),
    base_dist_(0, bases_.size() - 1),
    total_weight_(operation_weight_.size()) {
    operation_weight_.fill(1);
}

sequence_generator::operation sequence_generator::get_random_operation() {
    std::uniform_int_distribution<unsigned int> op_dist(0, total_weight_ - 1);
    unsigned int n = op_dist(engine_), op = 0, weight = 0;
    for (; op < operation_weight_.size(); ++op) {
        weight += operation_weight_[op];
        if (n < weight)
            break;
    }
    return static_cast<operation>(op);
}

void sequence_generator::set_weight(operation op, unsigned int weight) {
    total_weight_ -= operation_weight_[static_cast<size_t>(op)];
    operation_weight_[static_cast<size_t>(op)] = weight;
    total_weight_ += weight;
}

std::string sequence_generator::generate_sequence(size_t length) {
    std::string sequence;
    sequence.reserve(length);
    for (size_t i = 0; i < length; ++i)
        sequence += get_random_base();
    return sequence;
}

void sequence_generator::mutate_sequence(std::string& sequence) {
    std::uniform_int_distribution<size_t> dist(0, sequence.length() - 1);
    size_t pos = dist(engine_);
    char b;
    switch (get_random_operation()) {
    case operation::change:
        b = get_random_base();
        std::cout << "Change base at position " << pos << " from "
            << sequence[pos] << " to " << b << '\n';
        sequence[pos] = b;
        break;
    case operation::erase:
        std::cout << "Erase base " << sequence[pos] << " at position "
            << pos << '\n';
        sequence.erase(pos, 1);
        break;
    case operation::insert:
        b = get_random_base();
        std::cout << "Insert base " << b << " at position "
            << pos << '\n';
        sequence.insert(pos, 1, b);
        break;
    }
}

void sequence_generator::print_sequence(std::ostream& out, const std::string& sequence) {
    constexpr size_t base_count = bases_.size();
    std::array<size_t, base_count> count = { 0 };
    for (size_t i = 0, n = sequence.length(); i < n; ++i) {
        if (i % 50 == 0) {
            if (i != 0)
                out << '\n';
            out << std::setw(3) << i << ": ";
        }
        out << sequence[i];
        for (size_t j = 0; j < base_count; ++j) {
            if (bases_[j] == sequence[i]) {
                ++count[j];
                break;
            }
        }
    }
    out << '\n';
    out << "Base counts:\n";
    size_t total = 0;
    for (size_t j = 0; j < base_count; ++j) {
        total += count[j];
        out << bases_[j] << ": " << count[j] << ", ";
    }
    out << "Total: " << total << '\n';
}

int main() {
    sequence_generator gen;
    gen.set_weight(sequence_generator::operation::change, 2);
    std::string sequence = gen.generate_sequence(250);
    std::cout << "Initial sequence:\n";
    sequence_generator::print_sequence(std::cout, sequence);
    constexpr int count = 10;
    for (int i = 0; i < count; ++i)
        gen.mutate_sequence(sequence);
    std::cout << "After " << count << " mutations:\n";
    sequence_generator::print_sequence(std::cout, sequence);
    return 0;
}



Go: package main

import (
    "fmt"
    "math/rand"
    "sort"
    "time"
)

const bases = "ACGT"



func mutate(dna string, w [3]int) string {
    le := len(dna)
    
    p := rand.Intn(le)
    
    r := rand.Intn(300)
    bytes := []byte(dna)
    switch {
    case r < w[0]: 
        base := bases[rand.Intn(4)]
        fmt.Printf("  Change @%3d %q to %q\n", p, bytes[p], base)
        bytes[p] = base
    case r < w[0]+w[1]: 
        fmt.Printf("  Delete @%3d %q\n", p, bytes[p])
        copy(bytes[p:], bytes[p+1:])
        bytes = bytes[0 : le-1]
    default: 
        base := bases[rand.Intn(4)]
        bytes = append(bytes, 0)
        copy(bytes[p+1:], bytes[p:])
        fmt.Printf("  Insert @%3d %q\n", p, base)
        bytes[p] = base
    }
    return string(bytes)
}


func generate(le int) string {
    bytes := make([]byte, le)
    for i := 0; i < le; i++ {
        bytes[i] = bases[rand.Intn(4)]
    }
    return string(bytes)
}


func prettyPrint(dna string, rowLen int) {
    fmt.Println("SEQUENCE:")
    le := len(dna)
    for i := 0; i < le; i += rowLen {
        k := i + rowLen
        if k > le {
            k = le
        }
        fmt.Printf("%5d: %s\n", i, dna[i:k])
    }
    baseMap := make(map[byte]int) 
    for i := 0; i < le; i++ {
        baseMap[dna[i]]++
    }
    var bases []byte
    for k := range baseMap {
        bases = append(bases, k)
    }
    sort.Slice(bases, func(i, j int) bool { 
        return bases[i] < bases[j]
    })

    fmt.Println("\nBASE COUNT:")
    for _, base := range bases {
        fmt.Printf("    %c: %3d\n", base, baseMap[base])
    }
    fmt.Println("    ------")
    fmt.Println("    Σ:", le)
    fmt.Println("    ======\n")
}


func wstring(w [3]int) string {
    return fmt.Sprintf("  Change: %d\n  Delete: %d\n  Insert: %d\n", w[0], w[1], w[2])
}

func main() {
    rand.Seed(time.Now().UnixNano())
    dna := generate(250)
    prettyPrint(dna, 50)
    muts := 10
    w := [3]int{100, 100, 100} 
    fmt.Printf("WEIGHTS (ex 300):\n%s\n", wstring(w))
    fmt.Printf("MUTATIONS (%d):\n", muts)
    for i := 0; i < muts; i++ {
        dna = mutate(dna, w)
    }
    fmt.Println()
    prettyPrint(dna, 50)
}