Question

Why the traits of plants in F2 generation of mendelian monohybrid cross , not blended
B) Because the factors are located at different loci
C) Because due to no crossing over
D) Because factors are found on different chromosomes
E) All of the above

Answer 1

The traits of plants in F2 generation of mendelian monohybrid cross not blended Because the factors are located at different loci, because due to no crossing over and because factors are found on different chromosomes (E) All of the above.

Explanation:

• In a Mendelian monohybrid cross the F2​ generation shows identical genotypic and phenotypic ratios.
• Mendel performed seven types of monohybrid crosses, each involving contrasting traits for different characteristics.
• Out of these crosses all of the F1 offspring had the phenotype of one parent and the F2 offspring had a 3:1 phenotypic ratio.
• As we saw last time if we start with true breeding parents (one homozygous dominant one homozygous recessive) all of the F1 progeny will be heterozygous and show the dominant phenotype and then these will give rise to a 3:1 ratio of phenotypes in the F2 generation in a monohybrid cross.
• Thus in monohybrid cross F1 plants have similar genotype.
• All are heterozygous tall.
• In F2 generation genotypic ratio will be 1:2:1. , i.e. 1 homozygous tall: 2 heterozygous tall: 1 homozygous dwarf.

Answer 2

All of the above.

Explanations:

• If F1 generation plants can reproduce without mating, the alleles segregate, one allele goes to one parent and the other allele goes to another parent.  

• This corresponds to the migration of half the number of chromosomes during meiosis.  

• This isolation is a random process, with a 50% chance that a particular allele will be passed to male or female germ cells.  

• Therefore, the genotype produced in the F2 generation is the same as the phenotype produced in this generation.  

• Therefore, the proportion of plants with pure genotype and plants with mixed genotype is the same as 50%.