Drosophila Genetics and Phenotypes

The video tutorial explains a genetic cross in Drosophila, focusing on the dominant and recessive alleles for body color and wing shape. A female fly heterozygous for both traits is crossed with a male fly with recessive traits. The tutorial guides viewers through setting up the cross, analyzing possible offspring phenotypes, and understanding the resulting phenotypic ratios.

In Drosophila, which body color is dominant?

• Recessive brown

• Ebony

• Wild-type brown

• Curly

What is the wing shape of a fly with a dominant allele?

• Recessive

• Wild-type

• Ebony

• Curly

What is the genotype of a male fly with ebony body color?

• Heterozygous dominant

• Homozygous dominant

• Heterozygous recessive

• Homozygous recessive

What phenotypic ratio is expected in the offspring from the described cross?

• 3:1

• 1:1:1:1

• 9:3:3:1

• 2:2

Which phenotype combination is possible in the offspring?

• Ebony body with wild-type wings

• Ebony body with curly wings

• Wild-type body with curly wings

• All of the above

What body color and wing shape does an offspring with a wild-type phenotype have?

• Ebony body, curly wings

• Wild-type body, wild-type wings

• Ebony body, wild-type wings

• Wild-type body, curly wings

Why were some phenotype combinations not filled in?

• They were not observed

• They were all the same

• They were not relevant

• They were not possible

What is the significance of a 1:1:1:1 phenotypic ratio?

• It indicates a monohybrid cross

• It indicates a dihybrid cross

• It indicates incomplete dominance

• It indicates codominance

Which of the following is a recessive trait in Drosophila?

• Dominant wing shape

• Ebony body color

• Wild-type wing shape

• Wild-type brown body