Describe Mendel’s Monohybrid experiment.
If we use alphabetical symbols for each gene then the capital letter is used for the trait expressed at the $F_{1}$ stage and the small alphabet for the other trait.
For example, in case of the character of height ' $\mathrm{T}$ ' is used for the Tall trait and ' $\mathrm{t}^{\prime}$ for the 'dwarf' and ' $\mathrm{T}$ ' and ' $\mathrm{t}$ ' are alleles of each other.
- Hence in plants the pair of alleles for height would be $TT$, $Tt$ or $tt.$
- Mendel also proposed that in a true breeding tall or dwarf pea variety the allelic pair of genes for height are identical or homozygous, $TT$ and $\mathrm{tt}$ respectively.
$TT$ and $\mathrm{tt}$ are called genotype of the plant while the descriptive terms tall and dwarf are the phenotyped.
As Mendel found the phenotype of the $F_{1}$ heterozygote $\mathrm{Tt}$ to be exactly like $TT$ parent in appearance he proposed that in a pair of dissimilar factors, one dominates the other (as in the $F_{1}$ ) and hence is called the dominant factor while the other characters/trait pairs that he studied.
Which one of the following cannot be explained on the basis of Mendel’s law of dominance?
Match List $I$ with List $II$
List $I$ | List $II$ |
$A$. Two or more alternative forms of a gene |
$I$. Backcross |
$B$. Cross of $F_1$ progeny with homozygous recessive parents | $II$. ploidy |
$C$. Cross of $F_1$ progeny with any of the parents | $III$. Allele |
$D$. Number of chromosome sets in plant | $IV$. Test cross |
Choose the correct answer from the options given below:
Some pure black mice were mistakenly mixed with hybrid black mice. The quickest way to discover whether one individual black mouse is pure is
A cross between one tall plant and one dwarf plant resulted in offspring having tall plants. What would be the genotype of offsprings ?
A true breeding plant producing red flowers is crossed with a pure plant producing white flowers. Allele for red colour of flower is dominant. After selfing the plants of first filial generation, the proportion of plants producing red and white flowers in the progeny would be