Question

practice it!
what genotype is missing from the following punnett square?
○ rr
○ rr
○ rr
○ r
punnett square with r, r at top; r, r at left. cells: rr, rr, rr,?

Explanation:

To determine the missing genotype in the Punnett square, we analyze the alleles from the rows and columns. The column headers are \( R \) and \( r \), and the row we're looking at (the second row) has the allele \( r \) (from the left - hand side of the row). For the cell with the question mark, we combine the allele from the column (\( r \)) and the allele from the row (\( r \)). When we combine two \( r \) alleles, the genotype is \( rr \). We can also check the pattern of the Punnett square. In the first row (with \( r \) on the left), when combined with \( R \) we get \( Rr \) and with \( r \) we get \( rr \). Following the same pattern for the second row (also with \( r \) on the left), combining with \( R \) gives \( Rr \) and combining with \( r \) should give \( rr \).

Answer:

rr