3. In maize, green (G) colour plant is dominant over yellow ( \( \mathrm{g} \) ), full (R) seed is dominant over shrunken(r) seed and coloured (C) grain is dominant over colourless (c). From the three point test cross data given below, determine the order of the genes, estimate the map distance between them, construct their linkage map, calculate the coefficient of coincidence and coefficient of interference. \begin{tabular}{|c|c|c|c|c|c|} \hline GCR & & 22 & \( \mathrm{gcR} \) & - & 0 \\ \hline \( \mathrm{gCr} \) & - & 23 & \( \mathrm{GCr} \) & - & 5 \\ \hline \( \mathrm{gCR} \) & - & 390 & \( \mathrm{gCr} \) & - & 5 \\ \hline \( \mathrm{Gcr} \) & - & 365 & \( \mathrm{GcR} \) & - & 59 \\ \hline \end{tabular}
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Chromosome 3 of corn carries three loci ( $b$ for plant-color booster, $v$ for virescent, and lg for liguleless). A testcross of triple recessives with $\mathrm{F}_{1}$ plants heterozygous for the three genes yields progeny having the following genotypes: $305+v$ lg, $275 b++, 128 b+l g, 112+v+$ $74++\lg 66 b v+, 22+++,$ and $18 b v \lg$. Give the gene sequence on the chromosome, the map distances between genes, and the coefficient of coincidence.
In corn, a triple heterozygote was obtained carrying the mutant alleles $s$ (shrunken), $w$ (white aleurone), and $y(\text { waxy endosperm }),$ all paired with their normal wildtype alleles. This triple heterozygote was testcrossed, and the progeny contained 116 shrunken, white; 4 fully wild type; 2538 shrunken; 601 shrunken, waxy; 626 white; 2708 white, waxy; 2 shrunken, white, waxy; and 113 waxy. a. Determine if any of these three loci are linked and, if so, show map distances. b. Show the allele arrangement on the chromosomes of the triple heterozygote used in the testcross. c. Calculate interference, if appropriate.
Waxy endosperm $(w x),$ shrunken endosperm $(s h),$ and yellow seedlings (v) are encoded by three recessive genes in corn that are linked on chromosome $5 .$ A corn plant homozygous for all three recessive alleles is crossed with a plant homozygous for all the dominant alleles. The resulting $\mathrm{F}_{1}$ are then crossed with a plant homozygous for the recessive alleles in a three-point testcross. The progeny of the testcross are $$\begin{array}{cccc} w x & s h & V & 87 \\ W x & S h & v & 94 \\ W x & S h & V & 3,479 \\ w x & s h & v & 3,478 \\ W x & s h & V & 1,515 \\ w x & S h & v & 1,531 \\ w x & S h & V & 292 \\ W x & s h & v & \frac{280}{10,75 t} \\ \text { Total } & & & 10,75 \end{array}$$ a. Determine the order of these genes on the chromosome. b. Calculate the map distances between the genes. c. Determine the coefficient of coincidence and the interference among these genes.
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