Question

What Is Mendelism?

Answer 1

Mendelism:

1. Mendelism is a term that refers to the single-gene trait's theoretical principles of heredity, which are taken from Gregor Mendel's principles, also known as Mendel's laws.
2. Gregor Mendel conducted several experiments on pea plants for seven years and then postulated the laws of inheritance.
3. Mendel's law of inheritance includes the law of dominance, the law of segregation, and the law of independent assortment.

Law of dominance:

1. The first law of inheritance is the law of dominance.
2. The law states that hybrid offspring will only inherit the dominant characteristics in the phenotype.
3. The alleles that suppress a trait are recessive traits, whereas the alleles that define a trait are known as dominant traits.
4. Monohybrid cross helped in proposing the law of dominance.
5. In a monohybrid cross, Mendel crossed two pure pea plants with opposing traits (one short and one tall).
6. Mendel named those first-generation offsprings as F₁ progeny and all the offspring produced by crossing tall plants (dominant trait) and dwarf plants (recessive trait) were tall ( heterozygous dominant or hybrid).
7. After that, Mendel crossed F₁ progeny, and both tall and dwarf plants were obtained in the F₂ generation.

Law of segregation:

1. The law states that every pair of alleles or genes in parents, divides and a single gene is transferred from each parent to their offspring. The passage of a particular gene in a pair is a chance event.
2. There are several alleles for a single gene.
3. Every organism inherits a pair of alleles for each gene.
4. During the process of gametogenesis, when gametes are produced by meiosis, Then the allelic pairs segregate, leaving each gamete with only one allele.
5. A gene has two alternate forms known as alleles. One allele is dominant while the other allele is recessive.

Law of independent assortment:

1. According to this law, discrete pairs of alleles pass onto the children without being dependent on one another and as a result, the inheritance of genes in a particular region of the genome has no effect on the inheritance of genes in another region.
2. A dihybrid cross was used to formulate the law of independent assortment.
3. In a dihybrid experiment, Mendel selected two traits, each with two alleles.
4. He crossed round-yellow seeds (dominant) and wrinkled-green seeds (recessive) and observed that all of the F₁ progeny were round-yellow.
5. He then self-pollinated the F₁ progeny and obtained four distinct phenotypes that are round-yellow, round-green, wrinkled-yellow, and wrinkled-green seeds in the phenotypic ratio of 9:3:3:1.