Analyze recombinant offspring, compare models, and export results. Use flexible inputs for coursework and labs. Turn raw counts into confident linkage estimates for decisions.
| Study Label | Recombinant Offspring | Total Offspring | RF % | Simple cM | Haldane cM | Kosambi cM |
|---|---|---|---|---|---|---|
| Example Cross 1 | 86 | 1000 | 8.60 | 8.60 | 9.44 | 8.69 |
| Example Cross 2 | 124 | 900 | 13.78 | 13.78 | 16.15 | 14.53 |
| Example Cross 3 | 210 | 1200 | 17.50 | 17.50 | 21.53 | 19.22 |
Recombinant Fraction: r = Recombinant Offspring / Total Offspring
Recombination Frequency: RF (%) = r × 100
Simple Map Distance: Distance (cM) = RF (%)
Haldane Mapping Function: d = -50 × ln(1 - 2r)
Kosambi Mapping Function: d = 25 × ln((1 + 2r) / (1 - 2r))
Use Haldane and Kosambi only when r is below 0.50. When r reaches 0.50 or more, the gene pair may act as unlinked.
Recombination frequency measures how often recombinant offspring appear in a genetic cross. It helps estimate linkage between two genes. Lower values suggest tighter linkage. Higher values suggest weaker linkage. This calculator turns raw offspring counts into clear mapping outputs. It reports recombinant fraction, percentage, parental count, and map distance. It also shows Haldane and Kosambi estimates. These models help when crossover interference may affect interpretation.
In practice, recombination frequency is based on observed recombinant progeny divided by total progeny. The result is often expressed as a percent. One percent recombination usually represents one centiMorgan of map distance in a simple estimate. That approximation works best for short intervals. Longer intervals may hide multiple crossover events. That is why mapping functions matter. Haldane assumes no interference. Kosambi adjusts for crossover interference. Comparing both can improve interpretation.
This page is useful for coursework, breeding studies, linkage analysis, and genetics review. Enter the recombinant count and total offspring. Then choose your rounding level and preferred mapping model. After submission, the page places the result under the header and above the form. That keeps interpretation visible during edits. You can also download the current result as CSV. A print friendly PDF option is included for reports, assignments, and record keeping.
Use the example table to validate your entries before working with live data. Check that recombinant offspring never exceed total offspring. If the observed fraction reaches or exceeds one half, the genes may behave as unlinked, or the data may need review. In those cases, Haldane and Kosambi distances are not reliable. The calculator flags that condition clearly. This supports faster checking, cleaner reporting, and better discussion of linkage, crossover frequency, and genetic map distance.
Because users often compare several crosses, the tool also keeps the form simple and repeatable. You can label each study, update counts quickly, and review rounded outputs without leaving the page. The layout works well on large screens and smaller devices. That makes it easier to check calculations during labs, lectures, fieldwork, or homework sessions. Clear outputs also support reports, revision notes, and quick instructor feedback. Consistent formatting helps teams review results and compare datasets with less confusion. Efficiently.
It shows the proportion of recombinant offspring in a cross. That value helps estimate how closely two genes are linked on a chromosome.
A recombination frequency near 50 percent suggests independent assortment. In practice, that means the genes may be unlinked, or the dataset needs another review.
RF is the observed recombinant percentage. Map distance is the estimated chromosomal distance, often expressed in centiMorgans, after applying a simple or corrected mapping model.
Use Haldane when you want a mapping function that assumes no crossover interference. It is helpful for comparing intervals under that specific assumption.
Use Kosambi when you want a mapping function that adjusts for crossover interference. It often gives a practical estimate for linked genes in real datasets.
Yes. The form accepts decimal input. That is useful for adjusted datasets, weighted averages, or processed values from larger analysis workflows.
The warning appears when the recombinant fraction is 0.50 or higher. At that point, Haldane and Kosambi distances are not dependable for linkage mapping.
The CSV button downloads the current result table values. The PDF button opens a print view so you can save the calculated result as a PDF.