A discussion of Mendelian genetics usually requires an understanding of some basic genetic terms, such as gene, allele, genotype (homozygous or heterozygous), phenotype (dominant or recessive), genome, and gene pool. These terms help explain how traits are inherited and expressed in living organisms.
7.2.1 Genes, Alleles and Loci
i) Genes
Each characteristic and function of the body is controlled by factor called gene. The parental traits are passed to their offspring in the form of genes. Therefore, a gene is the unit of inheritance. Basically, a gene is a specific segment of DNA, comprising a unique sequence of nucleotides that encodes the sequence of amino acid in a particular polypeptide. Mendel was the first person who proposed the idea of gene, he called them "factors" or "elementents" and used to represent the genes of different characteristics with alphabetical symbols. Each characteristic and function of the body is controlled by factor called gene. The parental traits are passed to their offspring in the form of genes. Therefore, a gene is the unit of inheritance.
For your information
The complete set of an individual's genes is called the genome. The number of chromosomes that carry the entire genome is referred to as a set of chromosomes, represented by "n" or monoploid. A cell with two sets of chromosomes is called diploid or 2n. In humans, the full genome is spread across 23 chromosomes, which make up one set. The term haploid is used to represent a cell that contains half than the number of chromosomes of somatic cells (body cells other than gametes).
offspring in the form of genes. Therefore, a gene is the unit of inheritance.
ii) Locus (Plural loci)
Now we know that the genes are found in chromosomes at specific positions called loci (singular locus). A locus is represented on both members of a homologous pair of chromosomes
Diagram image pending upload by Admin.