Tetrad Analysis Calculator
Tetrad Calculator is designed for tetrad analysis and demonstrations.
Unordered tetrads with four spores
Use this mode to calculate the recombination frequency between two genes. The map distance between
two linked genes are calculated according to the following formula:
cM = 50 * (TT + 6 * NPD) / ( PD + NPD + TT ).
Here PD stands for parental ditype, NPD stands for non-parental ditype, and TT stands for
tetratype. PD, NPD, and TT are calculated from the ascus genetic patterns.
Ordered tetrads with four spores
Use this mode to calculate the recombination frequency between the gene and the centromere.
The gene-centromere distance is calculated using the following formula:
cM = 1/2 ( % of second division segregation.)
Ordered tetrads with eight spores
Unlike yeast, several species of ascomycete fungi have linear tetrads with eight ascospores.
Analysis of asci types can be applied to determine the map distance between the locus
and its centromere.
The first-division segregation has the following patterns:
The second-division segregation has the following patterns:
Rare patterns that differ from a pattern by only one permutation of neighboring spores
are classified as belong to the pattern.
Calculate from PD, NPD, and TT
Calculations are made directly from the counts of parental ditype (PD), non-parental ditype (NPD),
and tetratype (TT).
To use demo, select a type and click on the Demo button.
1. Select type.
2. Click on "Enter Gene Names" to input gene names. Type in gene names and click on "Add".
3. To remove a gene name, type in the gene name, and click on the remove button.
4. Please note gene names are case sensitive.
5. Click on "Enter Parental Genotypes" to select for genotypes of parents.
6. Click on the spore diagrams in the left window to input ascus patterns. Click to change
from one parental genotype to another or to unknown.
7. After finished inputing ascus patterns, click on "Go" to calculate map distances.
Thanks for using our software! Please let us know your suggestions and comments.