In a population of weasels, black (B) and white (W) are co-dominant traits. The heterozygous genotype produces black and white spotted weasels. Consider the genetic cross shown in Punnett square. If there are 40 baby weasels born as a result of the cross, how many should be black?

Responses
A 00
B 55
C 1010
D 2020

1 answer

To determine how many of the 40 baby weasels should be black, we first need to analyze the genetic cross and Punnett square, given that black (B) and white (W) are co-dominant traits.

In a typical Punnett square for a cross between two heterozygous weasels (BW x BW), the possible genotypes are:

  • BB (black)
  • BW (spotted)
  • BW (spotted)
  • WW (white)

The expected ratio of phenotypes from this cross would be:

  • 1 BB (black)
  • 2 BW (spotted)
  • 1 WW (white)

This results in a ratio of:

  • 1 black : 2 spotted : 1 white

To put this into terms of the total number of weasels (40):

  • Total parts = 1 (black) + 2 (spotted) + 1 (white) = 4 parts
  • Each part represents 40 total weasels / 4 parts = 10 weasels per part

From this, we can calculate:

  • Number of black weasels = 1 part = 10 weasels

Thus, if there are 40 baby weasels born from this cross, 10 of them should be black.

The best answer from the options provided is not listed correctly. However, based on our calculation, the expected number of black weasels is 10. If we assume "1010" in option C is a typographical error or interpretation for '10', that would be the closest answer.