1. The chromosome theory launched the study of genetics, the branch of biology that focuses on the inheritance of traits. What are the rules of inheritance that Mendel discovered?
1. The chromosome theory launched the study of genetics, the branch of biology that focuses on the inheritance of traits. What are the rules of inheritance that Mendel discovered?
answer :
Inheritance can be defined as the process of how a child receives genetic information from the parent. The whole process of heredity is dependent upon inheritance and it is the reason that the offsprings are similar to the parents. This simply means that due to inheritance, the members of the same family possess similar characteristics.
It was only during the mid 19th century that people started to understand inheritance in a proper way. This understanding of inheritance was made possible by a scientist named Gregor Mendel, who formulated certain laws to understand inheritance known as Mendel’s laws of inheritance.
Mendel’s laws
The two experiments lead to the formulation of Mendel’s laws known as laws of inheritance which are:
- Law of Dominance
- Law of Segregation
- Law of Independent Assortment
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 the recessive traits while the alleles that determine the trait are known as the dominant traits.
Law of Segregation
The law of segregation states that during the production of gametes, two copies of each hereditary factor segregate so that offspring acquire one factor from each parent. In other words, allele (alternative form of the gene) pairs segregate during the formation of gamete and re-unite randomly during fertilization. This is also known as Mendel’s third law of inheritance.
Law of Independent Assortment
Also known as Mendel’s second law of inheritance, the law of independent assortment states that a pair of traits segregates independently of another pair during gamete formation. As the individual heredity factors assort independently, different traits get equal opportunity to occur together.
Key Points on Mendel’s Laws
- The law of inheritance was proposed by Gregor Mendel after conducting experiments on pea plants for seven years.
- Mendel’s laws of inheritance include law of dominance, law of segregation and law of independent assortment.
- The law of segregation states that every individual possesses two alleles and only one allele is passed on to the offspring.
- The law of independent assortment states that the inheritance of one pair of genes is independent of inheritance of another pair.
Conclusions from Mendel’s Experiments
- The genetic makeup of the plant is known as the genotype. On the contrary, the physical appearance of the plant is known as phenotype.
- The genes are transferred from parents to the offspring in pairs known as alleles.
- During gametogenesis when the chromosomes are halved, there is a 50% chance of one of the two alleles to fuse with the allele of the gamete of the other parent.
- When the alleles are the same, they are known as homozygous alleles and when the alleles are different they are known as heterozygous alleles.
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