MODEL
Linkage and recombination
Adjust recombination frequency in a dihybrid test cross.
Test cross a double heterozygote with ab/ab. Offspring classes reveal the gametes from the heterozygote.
At 0%, only parental combinations occur. At 50%, all four classes are equally frequent.
Each parental class = (100 − r)/2%; each recombinant class = r/2%. Assumes equal viability and no segregation distortion. Recombination cannot distinguish distant linked loci from unlinked loci at 50%; map distance is not always equal to observed recombination percentage.
Explain what you observed
Can two-point recombination exceed 50%?
Your study notes
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Connect this activity with your lesson notes and chapter practice.
Read a related learning guide →Practise Inheritance →Open the student notes folder ↗Concepts and sources
Curriculum connections: 10.3, 10.4. Selected concepts.
Read the supporting source ↗PMDC curriculum ↗Questions and explanations are original teaching material; these are not official exam questions.