Mendels Principles Mendel used mathematics and experimentati

Solution

Mendelian Laws or principles of Heredity:

1. Principle of Unit Characters:

Mendel assumed that the unit of hereditary characters is the factors of determiners which occur in pairs. One of each comes from the mother while the other comes from the father. The unit character or factor is now called as gene.

2. Law of Dominance:

When a pair of contrasting characters (alleles) are present together, only one of them expresses itself and the other remains suppressed of hidden The character which is expressed (or is visible) is called as dominant and the character which remains hidden is termed as recessive.

3. Law of Segregation or Purity of Gametes:

The allelic factors or genes present together in the hybrids segregate (separate) from one another and are placed in different gametes in the next generation.

4. Law of Independent Assortment:

When two or more pairs of contrasting characters are taken into consideration in a cross, each factor, assort or place itself independently of the other.

The Principle of Independent Assortment describes how different genes independently separate from one another when reproductive cells develop. We now know that this independent assortment of genes occurs during meiosis in eukaryotes. Meiosis is a type of cell division that reduces the number of chromosomes in a parent cell by half to produce four reproductive cells called gametes and this separation, or assortment, of homologous chromosomes is random. This means that all of the maternal chromosomes will not be separated into one cell, while the all paternal chromosomes are separated into another. Instead, after meiosis occurs, each haploid cell contains a mixture of genes from the organism\'s mother and father.

Another feature of of independent assortment is recombination. Recombination occurs during meiosis and is a process that breaks and recombines pieces of DNA to produce new combinations of genes. Recombination scrambles pieces of maternal and paternal genes, which ensures that genes assort independently from one another.

why was the discovery of the laws of heredity ignored by most scientists for more than 35 years.

Mendel\'s ideas on heredity and evolution were diametrically opposed to those of Darwin and his followers. Darwin believed in the inheritance of acquired characters and most important of continuous evolution. Mendel, in contrast, rejected both, the inheritance of acquired characters as well as evolution. The laws discovered by him were understood to be the laws of constant elements for a great but finite variation, not only for culture varieties but also for species in the wild. As the Darwinians won the battle for the minds in the 19th century, there was no space left in the next decades for the acceptance of the true scientific laws of heredity discovered by Mendel.