Polyploidy is advantageous in plants as this condition enhances the useful traits that can be exploited for commercial farming. The useful traits that are enhanced by polyploidy include the bigger size, the resistance to adverse biotic and abiotic factors and increased metabolite production. Haploid plants can be used to produce tetraploid varieties by physical and chemical mechanisms, as follows:
Exposure of the newly developing plants to temperature shock induced polyploidy. This is achieved by inducing a sudden change in the temperature in which the target plants are developing.
Colchicine is a spindle poison and interferes with the formation of spindle fibers during mitosis. Thus, as the spindle fiber formation is interfered with, chromosomes do not segregate into the daughter cells equally, leading to nondisjunction. At higher concentrations, colchicine can also induce the nondisjunction of entire sets of chromosomes. Thus, colchicine can be used to produce tetraploid plants that are homozygous for all genes in a series of steps.
One other method to produce tetraploid plants from a haploid parent material is by fusing cells. The cell hybridization can be achieved by chemical or physical fusogens such as polyethylene glycol or electroporation respectively. Fused cells form hybrids with the chromosomal complement from each of the parental cell types, known as the 'heterokaryon'. Thus, cell hybridization techniques can be used to produce tetraploid plants from homozygous parents in a series of steps.
Gene families are those genes that are closely related and have developed from a common ancestral gene in the course of evolution. There are several cellular proteins encoded by gene families, especially in the life forms that occupy the higher levels of the evolutionary tree. Myosins, globins and glucose transporters are a few examples for groups of proteins that are encoded by gene families.
A few more examples of the gene families are the immunoglobulin superfamily, the major histocompatibility complex, the G-proteins gene family, and the myosin gene family.
The proteins of some of the gene families are tabulated below:
The gene families are important at the cellular level as they can perform more functions with subtle differences when compared to a single gene product. Also, the protein product of each of the genes in a family can be differently expressed based on the need or on the stage of development.
A gene family is a group of two or more genes that were produced by a duplication of a single ancestral gene.
Gene families are produced over time as the duplicated genes are present grouped together and are inherited. Each of the genes in the gene family might even accumulate mutations, thus forming closely related gene families over timE.Certain gene families have biological significance in terms of gene functions. Paralogs are the genes of a single species and are as a result of the gene family formed by a single ancestral gene. Such clusters of genes that form a gene family can bring about an important function, contributing to the evolutionary process. An example of such a gene family is the globin gene family. While the ancestral gene would have expressed only one type of globin molecule, thus performing one function, the formation of the globin gene family resulted in the production of several globin molecule types, each with a distinct function. Thus, the formation of a gene family can result in complex functions as can be important for the evolutionary development.