Question

explain the mechanism of hereditary changes

Answer 1

hi dear
.
heredity changes bcz of variation

Answer 2

The mechanism of heredity is dependent upon the behaviour of chromosome and the gene they carry some facts regarding characters.

I) A mixed population of plant species having heredity variation is used by the breeder to select plants with traits or characters for development of improved variety. E.g. Seed colours, size, plant height, leaf size, shape, disease resistant etc. Heritable variation results when different plants exhibit contrasting form of these characters. The contrasting traits are determined by alternative form of gene and their interaction.

II) The genes are located on the chromosome and are determine of the characters of a plant. These genes are having specific position on the chromosome and are duplicated when the chromosome divide.

The alternative form of a gene called alleles, which determine contrasting form of characters. The genes may be dominant or recessive (R or r). The plant with similar identical genes at a given locus on homologous chromosome are said to be homozygous and with unlike genes are said to be heterozygous. The appearance of plant is phenotype, while genetic constitution is genotype. The chromosomes are red shape body present in a nucleus of cell. They carry genes hence important in heredity. A chromosome occurs singly (haploid) in spores and in pairs (diploid) in body cell. The chromosome number is constant in any species and it divides longitudinally during mitosis and homologue chromosome separate during moysis. The mechanism of heredity can be explained with a single gene characters.