Rules for the Inheritance of Traits Mendel’s Contribution
Gregor Johann Mendel, often referred to as the ‘Father of Genetics’ has framed laws of inheritance. He had used pea plants for his experiments which are easy to grow and have greater number of visible characteristics like tall/dwarf, white/violet, wrinkled seeds.
- During his experiments there were some factors controlling the traits, which are now known as genes.
- And genes are present as a pair for a specific trait and are known as alleles.
- The tallness in a plant as a dominant trait, is denoted by ‘T’ and shortness in the plant would be a recessive trait, denoted by ‘t’ . thus the plant will be tall if it’s allele are ‘TT’ or ‘Tt’ .
- When the alleles of the genes have the same allele for a trait, they are termed as homozygous. Ex: ‘TT’ or ‘tt’ .
- And when the alleles of the genes have the different alleles for a trait, they are termed as heterozygous. Ex: Tt.
- The morphological expression of a single character is termed as the phenotype. Ex- tallness or shortness.
- Whereas the genetic constitution or the allele pair for a specific trait is termed as the genotype.
- He uses a statistical method known as Punnett square for predicting the possible genotype and phenotype of the offspring.
He conducted his experiment to find two types of inheritance namely:
Monohybrid Inheritence
Mendel took a tall (TT) and (tt) pea plant, crossed it to get the offspring. The first generation or F1 were all found to be tall showing only one of the trait of the parent. Then he self-pollinated the parent and the F1 plants. The offspring came out to be all tall, but the offspring of the F1 plants, the F2 generation did not have all tall plants. A quarter of them were short, which indicates that both traits of the parent was inherited by F1 generation. So, the genotype is – 1:2:1 and the phenotype is – 3:1. The inheritance of a trait by a pair of single alleles of a gene is termed as monohybrid inheritance.
Dihybrid Inheritence
When a pea plant with a two different traits; a plant with round green color seed (RRyy) is crossed with wrinkled yellow seed (rrYY) plant. The F1 generation turned out to have round yellow seed, RrYy, which showed the dominant traits to be round shape and yellow color. When the F1 generation were self pollinated, the F2 generation had greater variations than the parent and new combination also came up. So, the genotype is 9 different and the phenotype is 9:3:3:1. The inheritance of different trait by two pairs of alleles for it is termed as dihybrid inheritance.
Inherited Traits
Inherited Trait is a fundamental concept in genetics that explains how genes are passed from parents to offspring. Genes are the instruction that tells our bodies how to grow and develop properly and, to an extent, determine what we exhibit. Inherited traits are responsible for shaping the biological identity of an individual. These are the characters that are passed down from one generation to the next generation. This article explores the concept of inherited traits with the help of Mendel’s experiment and its applications in the field of genetics.
Table of Content
- What are Inherited Traits?
- Examples of Inherited Traits
- Types of Inherited Traits
- How do Traits Get Expressed?
- What are Acquired Traits?
- Difference Between Acquired and Inherited Traits
- Rules for the Inheritance of Traits Mendel’s Contribution