Question

Beagles have floppy ears but Chihuahuas have ears that stand upright. All hybrid puppies exhibit upright ears. Assume that this trait is controlled by a single gene, called EAR. Complete the Punnett square to show the cross between the purebred beagle and Chihuahua parents. Identify the dominant and recessive alleles. ​

Answer 1

Step-by-step explanation:

To complete the Punnett square for the cross between a purebred beagle and a Chihuahua, we need to identify the dominant and recessive alleles for the trait of ear type.

Let's use the letter "E" to represent the dominant allele for upright ears and the letter "e" to represent the recessive allele for floppy ears.

Purebred beagle: Ee (one dominant allele for upright ears, one recessive allele for floppy ears)

Chihuahua: ee (two recessive alleles for floppy ears)

Punnett square:

| E | e |

--------------------

E | EE | Ee |

--------------------

e | Ee | ee |

In the Punnett square, the top row and left column represent the possible alleles from the beagle parent, and the side row and bottom row represent the possible alleles from the Chihuahua parent.

As seen in the Punnett square, all the hybrid offspring (F1 generation) will have the genotype Ee, indicating that they will exhibit upright ears. The dominant allele "E" for upright ears is expressed in the presence of even one copy, while the recessive allele "e" for floppy ears is only expressed if both copies are present.

Therefore, in this cross, upright ears (represented by the dominant allele) are the dominant trait, and floppy ears (represented by the recessive allele) are the recessive trait.