The Genotypic variations Are variations in genotypes between individuals of the same species or between different species as a result of genetic mutation, gene flow or something that occurred during meiosis.
Genotypic variations between individuals of the same or different species are the result of genetic mutation, genetic flow or some occurrence during meiosis.
Genotype is the genetic map of an individual. It is the code that determines how everything will be formed. On the other hand, the phenotype is the physical result of the genotype or the physical expression of the genes.
For example, the genotype is the genetic code that determines that the eyes are blue and the phenotype is the blue color of the eyes resulting from this event.
What is seen with the naked eye is the phenotype, however behind the phenotype exists a complex process of codes of genes or genotypes that determine how something will be.
Types of genotypic variations and examples
Continuous Variations
Continuous variations are those that are determined by the environment and by genes. These variations can be seen among several individuals of the same species.
Continuous variations tend to be gradual and small. Examples of such variations include body weight, height, color of hair and skin.
Skin color
The color of human skin varies from the darkest brown to the lighter tones. The pigmentation of the skin of each individual varies according to their genetics, being the product of the genetic makeup of their parents.
In evolution, human skin pigmentation evolved through a process of natural selection, primarily to regulate the amount of ultraviolet radiation that penetrated the skin, controlling the biochemical effects.
The substance that determines the color of the skin is called melanin. Individuals who are located in populations near the equator or who receive high amounts of UVR tend to have darker skin colors.
Skin color can also vary depending on sun exposure, resulting in tanned or darker skin.
The genetic mechanism behind the skin color is regulated mainly by the enzyme tyrosine, which creates the color of the skin, eyes, and hair.
Differences in skin color can also be attributed to differences in size and distribution of skin melanomas.
There are several genes that can determine an individual's skin color. The MC1R gene determines what melanin the body produces; The KITLG and ASIP genes also have mutations associated with lighter skin color.
As well as these, there are many other combinations of genes that play a role in melanin production and skin color.
Hair color
Hair color is the pigmentation of hair follicles thanks to two types of melanin: eumelanin and pheomelanin.
Generally, if there is more eumelanin present, the hair color will be darker; If there is less eumelanin present, the hair will be lighter.
Melanin levels in hair can change over time, causing hair color to change. A person may also have different colors of follicles in their body.
The darker the hair of a person, the more individual hair follicles will have on your scalp.
The scale that differentiates hair tones is called the Fischer-Saller scale and uses these designations: A (very clear), B to E (light blonde), F to L (blonde), M to O To T (light brown to brown), U to Y (dark brown to black); The Roman numerals I to IV determine the red and the V to VI the reddish blondes.
It is not yet clear all the elements that determine hair color. It is believed that at least two different pairs of genes determine hair color.
However, this model does not take into account the different tones between the colors or explain why the hair sometimes darkens when a person grows old.
Height
Height is the distance from the feet to the head of the human body. When populations share the same genetic basis and environmental factors, mean height is a common feature of the group. Genetics is a big factor in determining the height of individuals.
An exceptional variation, such as more than 20% within a population, can sometimes be the cause of factors such as dwarfism or gigantism. These medical conditions are caused by specific genes or Anomalies in the endocrine system .
The genetic potential and a number of hormones, discounting some disease, are basic determinants to determine the height of a person. Other factors include the genetic response to external factors such as diet, exercise, environment, and life circumstances.
A particular male genetic profile called Y-haplotype I-M170 is related to height. The ecological information shows that the more the frequency of this genetic profile increases in the population, the more it increases the average male height in that place.
Discontinuous Variations
Discontinuous variations influence specifically and only on genes. It can be said that a variation is discontinuous when the element is clearly expressed as different and is only determined genetically.
In addition, they can not suffer alterations throughout the life of an individual. Many hereditary diseases such as albinism or dwarfism, in addition to blood type, fall into this category.
Blood type
Blood type is a blood classification based on the presence or absence of antibodies and antigenic substances. The blood type is inherited from the parents.
If a pregnant woman carries a baby with an antibody opposite her, such as a factor + and the baby is - you will need to follow a special treatment to bring the pregnancy to term.
Dwarfism
This disease is manifested when an individual is of unusually small stature. The most common cause is achondroplasia, a disorder that is caused by the presence of a failed allele in the genome.
This condition is a mutation in the growth receptor; Causes the FGFR3 gene to inhibit bone growth.
Recent studies suggest that this defect is inherited specifically from the father and becomes more common if the father reproduces after the age of 35.
References
- Human height. Retrieved from wikipedia.org.
- Genotypic variation: definition and example. Retrieved from study.com.
- Blood type. Retrieved from wikipedia.org.
- Retrieved from wikipedia.org.
- Continuous and discontinuous variations. (2015) Recovered from slideshare.com.
- Human skin color. Retrieved from wikipedia.org.
- Genetic and phenotypic variation. Retrieved from studentreader.com.
- Human hair color. Retrieved from wikipedia.org.