You Are Trying to Map a Human Gene Thought to Be

You are trying to map a human gene thought to be involved in cat allergies.Because you know this gene is on Chromosome 20, you decide to examine the linkage of several SNPs located on Chromosome 20 with respect to the gene involved in cat allergies.You have obtained DNA from 10 individuals, and you know whether they are allergic to cats.Your SNP results are shown in Table 19-24. $\begin{array}{l}\text { allergic to }\\\begin{array}{cccccc}\text { cats? } & \text { SNP1 } & \text { SNP2 } & \text { SNP3 } & \text { SNP4 } & \text { SNP5 } \\\hline \text { yes } & - & + & + & + & - \\\text { no } & - & + & - & - & + \\\text { no } & - & - & - & - & + \\\text { yes } & + & + & + & - & - \\\text { yes } & + & - & + & + & + \\\text { yes } & - & - & + & + & - \\\text { no } & + & + & - & - & + \\\text { yes } & + & + & + & + & - \\\text { yes } & - & - & + & + & + \\\text { no } & + & -&- & -& -\end{array}\end{array}$

Table 19-24 (+ indicates the presence of SNP)
A.Which SNP is most likely to be tightly linked to the gene involved in cat allergies? Explain your answer.
B.Of the SNPs tested above, which is likely to be the next closest to the gene responsible for the allergic state? Why?