Question

question 4 of 4 > stacked refer to the table. a biologist studying flies made two crosses as shown in the table. parental cross f₁ genotype numbers of individuals xxyy 1004 xxyy 998 xxyy × xxyy xxyy 5 xxyy 7 zzyy 796 zzyy 793 zzyy × zzyy zzyy 215 zzyy 220 what can be inferred about the genes x, y, and z? the genes for all three are on the same chromosome, and y is closer to z than it is to x. the genes for all three are on the same chromosome, and y is closer to x than it is to z. the genes for x and y are on the same chromosome, and the gene for z is on a different chromosome. the genes for z and y are on the same chromosome, and the gene for x is on a different chromosome.

Explanation:

Recombination frequency is used to determine gene - linkage. Low recombination frequencies indicate genes are close on the same chromosome. For the cross $XxYy\times xxyy$, the recombinant genotypes ($Xxyy$ and $xxYy$) have low numbers, showing $X$ and $Y$ are linked. For the cross $ZzYy\times zzyy$, recombinant genotypes ($Zzyy$ and $zzYy$) are also present. The fact that the $X - Y$ cross results are distinct from the $Z - Y$ cross results implies $X$ is on a different chromosome while $Z$ and $Y$ are on the same chromosome.

Answer:

The genes for Z and Y are on the same chromosome, and the gene for X is on a different chromosome.