Genotype Examples


The genotype is the DNA sequence of the genetic makeup of a cell, organism or individual, which determines a specific characteristic of that cell, organism, or individual. In other words, the genetic constitution of an organism is referred to as its genotype and describes an organism's complete set of genes. The genotype of an organism is the inherited map it carries within its genetic code. Not all organisms with the same genotype look or act the same way because appearance and behavior are modified by environmental and developmental conditions. Likewise, not all organisms that look alike necessarily have the same genotype.

Genotype is what makes the trait; the information within a gene, and is determined by the makeup of alleles, a word that refers to the form of a gene that produces different effects. When two alleles contain information the genetic makeup of an organism results in some physical characteristics distinguishing that organism from others.

Genotypes can only be determined by biological tests, not observations. Genotype is an inherited trait and hereditary information passed by the parents. The entire genetic information about an organism is contained in a genotype. This genetic information passed from parent to child is responsible for genetic traits such as eye color, height, hair color, the sound of the voice, certain diseases and various behaviors.

Internally coded information that is carried by all organisms is the genotype. The cells are produced according to a genotype and are manifested in an outward, physical appearance which is called the phenotype. Without genotype there is no phenotype. Thus, all the physical parts, the molecules, cells and other structures, are built and maintained by cells following the instructions given by the genotype. As these physical structures begin to act and interact with one another they can produce larger and more complex phenomena such as metabolism, energy utilization, tissues, organs, reflexes and behaviors. The genotype that carries the genetic information determines a number of physical characteristics because the entire genetic information about an individual is contained with the genotype.

Examples of Genotype:

1. Height

For an individual's gene makeup there is tall variety (T) and there is short variety (s). T and s are called the alleles. The combination of these determines the height. If T is considered to be the dominant of the two out of the four possible combinations (Ts, ss, TT, sT) it is determined the individual to be pure breed and carry the height of the T genetic information. As a result, the probability of the offspring being short is 1 in 4.

2. Freckles or no freckles

Again the information that is passed from parent to child is carried in the cell of the genotype. Whichever genotype becomes the dominant one determines if the child develops freckles or not.

3. Lactose intolerance

If the trait of lactose intolerance is passed from the dominant parent to the child the probability that the child will also be lactose intolerant is extremely high.

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