Genetic information is passed to the next generation through inheritance via reproduction. Reproduction is a fundamental characteristic exhibited by living entities wherein two parents from the opposite genders are involved to produce a new offspring.
Inheritance Through Different Stages Of Reproduction
The sperm is the male sex cell and the egg is the female sex cell. These sex cells contain genetic information, they fuse to form the zygote. Through various stages of cell division, the DNA splits and is transferred to the child. The new offspring hence inherits half its genes from each of its parents. We inherit genes from our parents and the varying combinations of these genes make us different and unique. Hence inheritance of genes governs the characteristics of living entities.
During the event of sexual fertilization, DNA from both the parents combine. This blend of DNA is unique to every individual as we receive 50% of the DNA from each parent, who in turn have received 50% of their DNA from their parents and so on. Genes are letters, precisely- a series of letters which serves as the blueprint of our body, safely preserved in the cell nuclei. The letter sequences possess genetic information in order to build specific molecules. Our cells are diploid and contain two sets of 23 chromosomes except for the gametes or the sex cell which are haploid in nature and have one set of chromosome.
The process of fertilization produces a fertilized egg – the zygote. It has the two sets of chromosomes from both the parents and detailed set of instructions which are required to produce more cells and ultimately an individual. Thus, each cell in the offspring contains genetic information from both the male and female parent. The evidence of inheritance can be examined and observed by comparing certain characteristics with his/her immediate family members. Some of these characteristics could be the color of eye and hair, height, complexion, etc. Along with passing characteristics, mutations, if any, can also be passed from the parents to the offspring.
Mutations are the alterations in the sequences of DNA caused due to mutagens. This is how genetic disorders could be inherited and passed to the next generations.
Out of the many disorders that are inherited, listed below are four types of genetic disorders that are inherited.
- Multifactorial Inheritance – Example: Alzheimer’s disease
- Single gene Inheritance or Monogenetic disorders – Example: Sickle-cell anemia
- Mitochondrial Inheritance – Example – LHON
- Chromosome abnormalities – Example: Turner Syndrome
Q.1. What is codominance?
A.1. It is an inheritance pattern in which alleles are neither recessive nor dominant.
Q.2. What is a Punnett square?
A.2. It is a chart depicting all possible combinations of alleles that can result from a genetic cross.
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|Genetics: Principles of Heredity|
|Molecular Basis of Inheritance|
|Mendel’s Laws of Inheritance|