If the parental lines are vg+pr and vgpr+

If the parental lines are vg+pr and vgpr+, what allele combinations would be expected in the recombinant genes?

The correct answer and explanation is:

Sure! Let’s break this down step by step.

Question Restatement:

Parental lines are vg+ pr and vg pr+.
What allele combinations would be expected in the recombinant genes?

Answer:

The parental genotypes are:

• vg+ pr
• vg pr+

Since these are linked genes on the same chromosome, the parental chromosomes are:

• One chromosome: vg+ (wild type for vg) and pr (mutant for pr)
• The other chromosome: vg (mutant for vg) and pr+ (wild type for pr)

The recombinant genotypes will be the new combinations formed by crossing over between these two linked genes:

• vg+ pr+
• vg pr

Explanation:

In genetic crosses involving two linked genes, the parental alleles are found together on the same chromosome, inherited as a block unless crossing over occurs during meiosis. The parental alleles here are vg+ paired with pr, and vg paired with pr+. The “+” denotes the wild-type (normal) allele, and the others (vg, pr) are mutant alleles.

Because the genes vg (vestigial wings) and pr (purple eyes) are linked, the parental chromosomes are:

• Chromosome 1: vg+ (normal wing) and pr (mutant eye)
• Chromosome 2: vg (mutant wing) and pr+ (normal eye)

When a crossover event happens between the vg and pr loci during meiosis, the alleles are exchanged, producing recombinant chromosomes with new allele combinations that differ from the parents.

Recombinant chromosomes will carry:

• vg+ pr+ (both wild-type alleles)
• vg pr (both mutant alleles)

This occurs because the crossover swaps alleles between the homologous chromosomes.

To summarize:

These recombinant genotypes arise at a frequency proportional to the recombination rate between the two genes, which depends on their physical distance on the chromosome. If the genes are close, recombinant offspring are fewer; if far apart, recombination frequency increases.