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Genetics

Genetics means the units in the cells of a living that control its physical characteristics of an organism. Genetics is the study of genes and heredity. It is the central to the life of an individual which influences our physical features. Gene is a region or venue of DNA that encodes a working or functional RNA or protein product, and is the molecular unit of heredity.


Variation

Variation means changes that occur or exist between individuals. Variation is any difference between cells, individual organisms, or groups of organisms of any species induced either by genetic differences (genotypic variation) or by the effect of environmental factors on the expression of the genetic potentials (phenotypic variation). It can be described as been continuous or discontinuous. 

Continuous Variation: these variations are mainly morphological and physical. Examples are: height, weight, length, skin, pigmentation(colour), colour of the eyes and finger prints.Also in continuous variation there is a complete range of measurement from one extreme to another.

Discontinuous Variations are mainly physiological variations. Example are blood groups, tasters, tongue rolling, sickling characters or traits, heamophilia. Heamophilia is the inability of the blood to clot. Also discontinuous variations is controlled by alleles of a single gene or a small number of gene.

There are characters or traits that can be found among various species of organisms. These variations can either be heritable or non- heritable.





The heritable characters or variations: are those that can be passed through the germ line (sperms or eggs) during the process of sexual reproduction or through attributes passed down through the soma such as leaves, stems and roots which serve as (asexual reproduction). Asexual reproduction occurs in plant, while Sexual reproduction occurs in animals, involving two parents.

In sexually reproduction organism, the sperm, pollen and egg constitute the germ line containing the characters in parents which are passed on to the offspring, thus, the germ lines are the bearers of information that controls the development of the offspring.

The non-heritable characters or variations: Some errors that do not involved the germ line may be manifested in the parents, but are not transmissible to the offspring, such errors like accidents are referred to as non- heritable character e.g amputation of limbs or blindness that result from accident can not be transferred inherited by the offspring, culture traits such as languages and mannerisms are passed from the parent to the offspring, also cultural traits depends on cultural environment.

Submitted by: Annix

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