Phylogenetic Distance Calculator

Phylogenetic distance measures how evolutionarily diverged two species are by comparing differences in their DNA sequences — a core calculation in evolutionary biology and taxonomy. Paste your Species 1 and Species 2 DNA sequences into the Phylogenetic Distance Calculator, then select a Distance Calculation Method (Jukes-Cantor, Kimura 2-Parameter, Tamura-Nei, or P-Distance), a Gap Treatment approach, and the number of Bootstrap Replicates. You'll get the Evolutionary Distance in substitutions per site, along with sequence similarity, transition and transversion counts, and the Ti/Tv ratio.

DNA sequence for first species (nucleotides A, T, G, C)

DNA sequence for second species (nucleotides A, T, G, C)

Choose evolutionary distance calculation method

How to handle alignment gaps in sequences

Number of bootstrap replicates for statistical support

Results

Evolutionary Distance

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Sequence Similarity

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Transitions

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Transversions

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Ti/Tv Ratio

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Frequently Asked Questions

What is phylogenetic distance and why is it important?

Phylogenetic distance measures the evolutionary relationship between species based on genetic differences. It quantifies how much two species have diverged from their common ancestor, helping researchers understand evolutionary relationships and timelines.

Which distance calculation method should I choose?

Jukes-Cantor is suitable for closely related sequences with simple evolutionary models. Kimura 2-Parameter accounts for different transition/transversion rates. Tamura-Nei considers base composition differences. P-distance is the simplest method counting only observed differences.

How should I handle gaps in my sequence alignments?

Pairwise deletion removes gaps for each pair comparison, retaining maximum data. Complete deletion removes all positions with gaps in any sequence. Ignore gaps treats gaps as missing data without affecting distance calculations.

What is the Ti/Tv ratio and what does it indicate?

The transition/transversion ratio compares purine-to-purine or pyrimidine-to-pyrimidine changes (transitions) versus purine-to-pyrimidine changes (transversions). Higher ratios indicate more transitions, which are typically more common in evolution.

How many bootstrap replicates should I use?

100-1000 bootstrap replicates provide statistical confidence in distance estimates. More replicates increase accuracy but require more computation time. 100 replicates are usually sufficient for most analyses.

What sequence formats are accepted?

The calculator accepts plain DNA sequences (ATGC) or FASTA format sequences. Remove any headers or formatting and ensure sequences contain only standard nucleotide characters (A, T, G, C, and optionally N for unknown bases).

How accurate are phylogenetic distance calculations?

Accuracy depends on sequence quality, length, and evolutionary model appropriateness. Longer sequences provide more reliable estimates. Consider using multiple methods and comparing results for important analyses.