A homozygous purple flower variety of pea plant [PP] is crossed with a white flower variety of pea[pp]. Answer the following questions by using Punnett square:-
i) Mention the phenotype and genotype of the F1 and generation offsprings.
ii) If the offsprings of the F1 and generation are crossed, what will be the phenotypic ratio and genotypic ratios of the F2 generation?
iii) State Mendel's Law of dominance.
iv) What is the scientific name of the pea plant?
v) Name two genetic diseases in humans
A homozygous purple flower variety of pea plant [PP] is crossed with a white flower variety of pea[pp]. Answer the following questions by using Punnett square:-
i) Mention the phenotype and genotype of the F1 and generation offsprings.
ii) If the offsprings of the F1 and generation are crossed, what will be the phenotypic ratio and genotypic ratios of the F2 generation?
iii) State Mendel's Law of dominance.
iv) What is the scientific name of the pea plant?
v) Name two genetic diseases in humans
i) The cross is studied by monohybrid cross since it is involving only one trait which is the flower color. During the F1 generation: Gametes: P and p. So, during F1 generation, the progenies are all of the genotypes: Pp or heterozygous purple flowers and are all purple flowers (phenotype similar). The white color trait has been suppressed by the dominant trait color, purple
Phenotypic Ratio =1:1
Genotypic Ratio=1:1
(ii) Upon further crossing this F1 progeny with each other,
Gametes: P and phenotypic Ratio = 3:1 (3 Purple flowers and 1 White flower)
Genotypic Ratio = 1:2:1 (1 Homozygous Purple, 2 Heterozygous Purple, and 1 Homozygous White flower)
iii) Law of dominance: This is also called Mendel’s first law of inheritance. According to the law of dominance, hybrid offspring will only inherit the dominant trait in the phenotype. The alleles that are suppressed are called recessive traits while the alleles that determine the trait are known as dormant traits.
iv) Scientific name of the garden pea is Pisum sativum.
v) a. Thalassemia: Thalassemia is a family of hereditary genetic conditions that limits the amount of hemoglobin an individual can naturally produce. This condition inhibits oxygen flow throughout the body.
b. Down's Syndrome: Typically, the nucleus of an individual cell contains 23 pairs of chromosomes, but Down syndrome occurs when there are three copies of the 21st chromosome.
i) The cross is studied by monohybrid cross since it is involving only one trait which is the flower color. During the F1 generation: Gametes: P and p. So, during F1 generation, the progenies are all of the genotypes: Pp or heterozygous purple flowers and are all purple flowers (phenotype similar). The white color trait has been suppressed by the dominant trait color, purple
Phenotypic Ratio =1:1
Genotypic Ratio=1:1
(ii) Upon further crossing this F1 progeny with each other,
Gametes: P and phenotypic Ratio = 3:1 (3 Purple flowers and 1 White flower)
Genotypic Ratio = 1:2:1 (1 Homozygous Purple, 2 Heterozygous Purple, and 1 Homozygous White flower)
iii) Law of dominance: This is also called Mendel’s first law of inheritance. According to the law of dominance, hybrid offspring will only inherit the dominant trait in the phenotype. The alleles that are suppressed are called recessive traits while the alleles that determine the trait are known as dormant traits.
iv) Scientific name of the garden pea is Pisum sativum.
v) a. Thalassemia: Thalassemia is a family of hereditary genetic conditions that limits the amount of hemoglobin an individual can naturally produce. This condition inhibits oxygen flow throughout the body.
b. Down's Syndrome: Typically, the nucleus of an individual cell contains 23 pairs of chromosomes, but Down syndrome occurs when there are three copies of the 21st chromosome.
