In this article, let’s see about how traits are made and three facts about it.
A specific characteristic of an individual is known as a trait that is determined by genes or the environment. The traits can either be qualitative or quantitative.
How are traits made from DNA?
All the traits of the organism are inherited from parents through the transmission of DNA. The information that determines the trait is carried by the genes. Each cell contains about 25,000 to 35,000 genes.
The traits of an organism depend on the complex mixture of interacting compounds that are present inside it. The proteins from the DNA (deoxyribonucleic acid) play a major role in determining the characteristic of the traits.
How are traits made from DNA?
The part of the DNA that determines the trait is known as a Gene- a basic unit of heredity. Different genes determine different traits. The DNA of an organism is a mixture of the mother’s and father’s DNA. The human DNA has 23 pairs of chromosomes, these chromosomes contain genes.
The genes of the body that determine the physical appearance is known as phenotype. The genetic makeup of the trait is known as genotype.
DNA contains information that makes proteins that are responsible for carrying out all functions of a living organism. Each trait is determined by a pair of genes that codes protein. The genes can either be dominant or recessive. If the individual contains two dominant or two recessive genes for a given trait then it is said to be a homozygous gene, if it contains one dominant and one recessive gene then it is called a heterozygous condition.
The traits are passed from the parents to the offspring when the male gamete and female gamete unite. The egg is fertilized with the sperm each of which contains 23 chromosomes and the resulting zygote will have 46 chromosomes in total.
The central dogma of life is the conversion of DNA to mRNA and mRNA to protein. The process of conversion of DNA to mRNA is known as transcription and the conversion of mRNA to protein is known as translation.
RNA is a single-stranded nucleic acid that is composed of ribose sugar, phosphate, and four nitrogenous bases (Adenine, Guanine, Cytosine, and Uracil). There are three types of RNA:
- rRNA (Ribosomal RNA)
- mRNA (messenger RNA)
- tRNA (transfer RNA)
The transcription process is performed by the RNA polymerase enzyme that uses the DNA strand as a template and forms a RNA strand. There are three stages:
The RNA polymerase binds to a sequence in the DNA known as a promoter and starts to separate the DNA strands and provides a single strand as a template for transcription.
The template DNA strand is scanned by the RNA polymerase, it reads each base at a time and the polymerase builds complementary nucleotides and makes the chain grow.
There are particular sequences called terminators that signal the RNA transcript to stop the process. Once the strand is transcribed, they release the RNA polymerase.
The mRNA formed undergoes a translation process in the ribosome of the cytoplasm. In this process, the mRNA is decoded and the amino acid chain is built. The nucleotides are read as a group of three and it is known as codons. Each codon codes for different amino acids, there is start codon AUG where the translation starts, and then the tRNA contains anticodon which binds with the matching mRNA and codes for amino acids.
The translation has three processes:
Once the tRNA reads the stop codon (UAG, UGA, or UAA) then the translation process stops and the polypeptide chain formed is released.
The polypeptide chain contains amino acids that are chemically altered and folded to form a distinct protein. The proteins are formed to determine the characteristic of each trait.
Difference between DNA and RNA:
|S.No||DNA (Deoxyribonucleic acid)||RNA (Ribonucleic Acid)|
|1.||It is double-stranded and found in the nucleus||It is single-stranded and found in the cytoplasm|
|2.||The sugar molecule is Deoxyribose||The sugar molecule is Ribose|
|3.||The bases are Adenine, Guanine Thyamine, and Cytosine||The bases are Adenine, Guanine, Uracil, and Cytosine|
|4.||Prone to UV damage||Not damaged by UV rays|
|5.||It mainly carries genetic information that is responsible for reproduction and development||It is involved in protein synthesis and also regulates gene expression|
|6.||There are two types of DNA |
1. Nuclear DNA
2. mtDNA (mitochondrial DNA)
|There are three types of RNA |
1.mRNA (mitochondrial RNA)
2.tRNA (transfer RNA)
3.rRNA (ribosomal RNA)
Traits are specific characteristic features of an individual which are determined either by the gene or the environment. the traits are passed from one generation to the other through DNA (Deoxyribonucleic acid).