Genetic linkage

In a three-point cross, the most numerous among the F2 offspring are:

• Double crossover progeny

• Single crossover progeny

• Progeny with parental traits

• Mutant progeny

In three-point mapping, the least frequent progeny are the ______ phenotypes.

• single crossover

• parental

• double crossover

• dominant

In a three-point cross, the gene whose position changes in the double crossover progeny is the ____________ gene.

• first

• middle

• recessive

• dominant

Calculate the distance between Wings size (vg) and Body colour (b)

• 0.18 m.u

• 18 m.u

• 180 m.u

• 1800 m.u

Is b (black body) and vg (vestigial wings) are linked? Why?

• Linked because the RF% is >50%

• Linked because the RF% is <50%

• Not linked because RF% is <50%

• Not linked because the presence of recombinant traits in F2 generation

Which of the chromosome part is non-sister chromatids?

• a

• b

• c

• d

Which is known as tetrads?

• a

• b

• c

• d

Tetrad consist of ______ chromatids

• 2

• 4

• 8

• 10

In a complete linkage between A and B genes, which of the following gametes will be formed?

• 
• 
• 

Alleles A and B are linked in ________ phase.

• coupling

• repulsion