Heredity

The process of transferring traits and characteristics from parents to kids through genes is known as heredity or hereditary. The offspring inherit their mother and father’s qualities and attributes, which are genetic information.

The reason you look so much like your parents is due to heredity and genetics. Genetics is a field of science that investigates living things’ DNA, genes, genetic diversity, and heredity.

Heredity

In the most basic sense, heredity refers to the transmission of traits or characteristics from one generation (parent) to the next (offspring). In sexual reproduction, heredity is clearly visible. This is due to the considerable variability of hereditary features in this process.

Variation occurs as a result of errors in DNA copying. Variation is significant because it helps evolution and is the foundation of heredity. Gene mutations, interactions between genes and the environment, and diverse combinations of genetic material all contribute to variation. Keep in mind that asexual reproduction can also result in variety. However, these differences are barely noticeable.

General Mendel- The Father of Genetics

Inheritance is the process of passing down characteristics or traits from one generation to the next. Both parents contribute equally to the inheritance of features in this situation. Gregor Mendel, commonly known as the Father of Genetics, did extensive research and studies on how features are passed down through generations.

He studied plant breeding and hybridization and performed experiments on pea plants to demonstrate how traits are passed down in living beings.

Theories of Heredity

Preformation Theory

Anton Van Leeuwenhoek proposed this idea after observing human sperm and naming them animalcules. According to him, when sperm is placed into a mother’s womb, where it receives sufficient nourishment and warmth from the mother, it can develop into a new individual. However, this was rejected because it does not explain the offspring’s maternal nature.

Particulate Theory

According to Mauperkius, a French biologist explained that each animal creates minute particles during reproduction, and new offspring are produced from the union of two parents’ particles. Another great English naturalist, Charles Darwin, proposed the hypothesis of pangenesis for character inheritance.

Pangenesis, according to him, are microscopic particles that originate in various regions of the body, connect with reproductive cells, and direct the progeny in the formation of the relevant part. This idea is not disproved since it fails to explain why inheritance occurs.

Mendel’s Law of Inheritance

According to Mendel, both the father and the mother contribute to the rules of inheritance of features in humans, resulting in an equal amount of genetic material in their offspring. Each of a child’s traits is influenced by the father and mother’s DNA, or DeoxyriboNucleic Acid. There will be two versions for the child, one from the father and one from the mother. Gregor Johann Mendel was the first scientist to focus on the fundamentals of trait inheritance.

Monohybrid Cross

It’s a cross between two plants with one set of opposing characteristics. For e.g., A cross between a tall pea plant and a small (dwarf) pea plant.

Observation & Conclusion

• First generation(F₁), the progeny were tall.
• In the second generation (F₂), 1/4th of the offspring were short and 3⁄4 were tall.
• The Phenotypic ratio is given by F₂ – 3: 1 (3 tall: 1 short)
• The Genotypic ratio is given by F₂ – 1: 2: 1 – (TT: Tt: tt)
• For tall plant, a single copy of “T” is enough. But if a plant has to be short, both the copies should be “t”.
• In Tt, ‘T’ is expressed and‘t’ is suppressed. Hence, the characters ‘T’ is the dominant trait and‘t’ is the recessive trait.

Dihybrid Cross

It’s a cross between two plants with two sets of opposing characteristics. This takes into account two different characters’ alternate qualities. For instance, a hybrid between a round pea plant with green seeds and a wrinkled pea plant with yellow seeds. The dihybrid cross is illustrated in detail in the diagram below.

F1 Gametes

Observation and Conclusion

The following observation is obtained:

• The F1 generation is made up entirely of hybrid plants. Because when RRyy crosses with rrYY, all offspring plants in the first generation are Rr Yy with round and yellow seeds. As a result, the Round and Yellow seeds are the most dominant.
• The phenotypic ratio in F2 is 9:3:3:1, and the genotype ratio is complicated.
• This demonstrates that the genes were inherited separately.

Sex Determination

Sex Determination refers to the processes through which an individual’s sex is determined. A distinct pair of chromosome in a diploid cell tells us the sex of an individual in diploid organisms with separate sexes. Humans are made up of 46 chromosomes. There are 44 pairs of autosomes and 2 pairs of sex chromosomes among these. Human chromosomes are fruit-fly-like and are divided into two types: X and Y chromosomes.

Conclusion

The process of transferring traits and characteristics from parents to kids through genes is known as heredity or hereditary. The offspring inherit their mother and father’s qualities and attributes, which are genetic information.

In the most basic sense, heredity refers to the transmission of traits or characteristics from one generation (parent) to the next (offspring). In sexual reproduction, heredity is clearly visible. This is due to the considerable variability of hereditary features in this process.

It’s a cross between two plants with one set of opposing characteristics. For e.g., A cross between a tall pea plant and a small (dwarf) pea plant. It’s a cross between two plants with two sets of opposing characteristics. This takes into account two different characters’ alternate qualities.