Analyze the DNA sequences of species $A, B$, and $C$ to determine their similarities and differences.
Species A: A-T-G-C-T-T-G-C-G-T-A-C-T-T-A-G-A-A-T-G
Species B: A-T-G-A-A-T-G-C-C-T-G-C-T-A-T-G-C-A-T-G
Species C: A-T-C-C-T-T-G-T-G-T-A-C-T-T-A-G-A-C-T-G
Answer (1)
The DNA sequences of species A, B, and C are aligned and compared.
The overall similarity across all three sequences is calculated as 50%.
The number of mismatches between each pair of sequences is determined: A vs B (7), A vs C (3), B vs C (10).
No unique bases are found that are specific to only one of the sequences. 50%
Explanation
Problem Analysis We are given three DNA sequences from species A, B, and C. Our goal is to analyze these sequences to determine their similarities and differences. This involves identifying conserved regions, unique regions, and mismatches between the sequences.
Sequence Alignment First, let's align the sequences and compare them position by position.
Species A: A-T-G-C-T-T-G-C-G-T-A-C-T-T-A-G-A-A-T-G Species B: A-T-G-A-A-T-G-C-C-T-G-C-T-A-T-G-C-A-T-G Species C: A-T-C-C-T-T-G-T-G-T-A-C-T-T-A-G-A-C-T-G
All sequences have the same length of 20 bases.
Overall Similarity Next, we calculate the percentage of positions where all three sequences have the same base. The number of positions where all three sequences match is 10. Therefore, the similarity percentage is:
20 10 × 100 = 50%
Pairwise Mismatches Now, let's identify mismatches between each pair of sequences:
A vs B: 7 mismatches
A vs C: 3 mismatches
B vs C: 10 mismatches
Unique Regions Next, we identify unique bases in each sequence. After comparing the sequences, we find that there are no bases that are unique to only one sequence.
Summary of Findings In summary, the three DNA sequences have a 50% similarity across all three species. The number of mismatches between each pair of sequences are as follows:
Species A and B: 7 mismatches
Species A and C: 3 mismatches
Species B and C: 10 mismatches
There are no unique bases specific to only one of the sequences.
Conclusion The analysis of the DNA sequences reveals a moderate level of similarity between the three species, with several mismatches observed between each pair. The overall similarity percentage is 50%, indicating that half of the positions are conserved across all three sequences.
Examples
DNA sequence analysis is crucial in various fields, including evolutionary biology, medicine, and forensics. For example, comparing DNA sequences of different species can help us understand their evolutionary relationships and identify genes responsible for specific traits. In medicine, DNA sequence analysis can be used to diagnose genetic diseases and develop personalized treatments. In forensics, DNA fingerprinting is used to identify individuals based on their unique DNA profiles. Understanding the similarities and differences in DNA sequences is fundamental to these applications.
