Gene G recombines with gene T at a frequency of 7%, and gene G recombines with gene R at a frequency of 4%.

Draw two possible genetic maps for these three genes, and identify the recombination frequencies predicted for each map.

Verified step by step guidance

1. <span>Step 1: Understand that recombination frequency is a measure of genetic linkage and is used to estimate the distance between genes on a chromosome. A 1% recombination frequency is equivalent to 1 map unit or 1 centimorgan (cM).</span>
2. <span>Step 2: Given the recombination frequencies, we have: G-T = 7% (7 cM) and G-R = 4% (4 cM). We need to determine the possible arrangements of these genes on a chromosome.</span>
3. <span>Step 3: Consider the first possible map: Place gene G in the middle. This would mean the map could be R-G-T, with R-G = 4 cM and G-T = 7 cM. Calculate the total distance between R and T.</span>
4. <span>Step 4: Consider the second possible map: Place gene T in the middle. This would mean the map could be G-T-R, with G-T = 7 cM and T-R = 4 cM. Calculate the total distance between G and R.</span>
5. <span>Step 5: For each map, verify the consistency of the recombination frequencies with the given data and ensure that the total distance between the outer genes matches the sum of the individual distances.</span>

Key Concepts

Recombination Frequency

Recombination frequency is a measure of the likelihood that two genes will be separated during meiosis due to crossing over. It is expressed as a percentage, indicating the proportion of offspring that exhibit a recombinant phenotype. For example, a recombination frequency of 7% between genes G and T suggests that 7% of the gametes will have a combination of alleles different from the parental types.

Genetic Mapping

Genetic mapping involves determining the relative positions of genes on a chromosome based on recombination frequencies. By analyzing how often genes recombine, researchers can create a map that shows the order and distance between genes. This is crucial for predicting inheritance patterns and understanding genetic linkage, which can influence traits in offspring.

Linkage and Gene Order

Linkage refers to the tendency of genes located close to each other on a chromosome to be inherited together. The order of genes can be inferred from recombination frequencies; genes that are further apart are more likely to recombine. Understanding the linkage and order of genes G, T, and R is essential for accurately drawing genetic maps and predicting recombination outcomes.