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 black weasels would be expected in a population of 40 weasels resulting from a genetic cross involving co-dominant traits, we first need to identify the genotypes involved.

Assuming that:

  • BB = Black weasel
  • WW = White weasel
  • BW = Black and white spotted weasel

From a cross between BB (black) and WW (white), the possible outcomes in a Punnett square would be:

  • 100% BW (black and white spotted)

From a cross between two heterozygous weasels (BW x BW), the Punnett square would give us:

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

This results in a ratio:

  • 1 BB : 2 BW : 1 WW

If we assume the total offspring are 40 weasels derived from a BW x BW cross, we can calculate the expected number of black weasels (BB).

From the ratio:

  • Total parts = 1 (BB) + 2 (BW) + 1 (WW) = 4 parts
  • Expected black weasels (BB) = 1/4 of total offspring = 40/4 = 10

Based on this calculation, if there are 40 baby weasels born as a result of the cross, the number of expected black weasels is 10.

So, the answer is C: 10.