Since the 19th century experiments have been conducted on the heredity of various organisms. The heredity was determined by observations of organisms – that the next generation gets one copy from each factor from each parent, and subsequently passing the factor on to following generations (Durmaz et al., 2015). The factors include for example colour, height, or shape of the organism. Pioneers Gregor Mendel and Augustinian Friar were scientist studying genetics scientifically. Gregor Mendel performed breeding experiments with hybridizing pea plants, in which different traits were traced. The traits included colour of the plants and round or wrinkled peas. The pioneer, after reporting the first breeding experiments, died in 1884. Little did he know that he would end up in biology textbooks.
Astounding results were observed by Mendel, the scientist saw traits were independently transmitted from each other (Dijk, Weissing, & Ellis, 2018). The independent transmission of traits is based on the position of genes on the corresponding chromosome. The progeny receives half of the chromosomes of both parents. If the gene is positioned on a chromosome – which is not passed down the lineage – the progeny does not express the gene. Therefore, if an experiment is conducted on various traits encoded by the corresponding genes. The progeny expresses different variation of traits in contrast to the parents.
Although, Mendel started the experiments on heredity of organisms. The scientist did not introduce the words “genetics” or “gene”. Later in the 20th, the scientific community century begun to focus on more breeding related experiments, and thereby referring to the results indicated by Mendel. The heredity of organisms would be called “genetics” and the factor that expresses the trait of a species was described as “gene” (Portin, Wilkins, 2017). It was the start of a new discipline in the scientific community.
Introduction to genetics
The introduction of the study genetics leaded to genetic research on a more molecular level. The molecular level experiments were more focussed on the structure and biosynthetic pathways that are needed to express a certain trait. In the first stages of genetic research on various structures and biosynthetic pathways, scientists suggested corresponding proteins were responsible for the induction of the perceived traits. However, following-up research leaded to the – todays well known double helix structured DNA – to be the encoding factor that expresses the perceiving trait.
Nowadays, DNA structures, which have the typical double helix structure, are seen everywhere. Genetic research elucidated more specification on the structure of the DNA strand and stated DNA was an information molecule (Travers & Muskhelishvili, 2015). The DNA strands are made up of so called “nucleic acids”, which are based on four nucleotides adenine (A), thymine (T), cytosine (C) and guanine (G). Groups of nucleic acids, three nucleotides, encode for the amino acids and amino acids are consecutive the basis of entire chromones. As it has been highlighted in modern society are the Homo Sapiens exist of 46 chromosomes. The chromosomes are the building blocks of the human genome.
Mutations and phenotypes
Progressive research broadened the insights on the DNA structures of various species. The DNA structure consists of information molecules, which encode for structural or active biosynthetic systems were the organisms are made up on. Genetic research has indicated changes on the prescribed encoded DNA strand. The changes are called mutations. Mutations are alterations in the DNA strand. The mutations can change a trait such as eye colour, skin colour or height. These traits are all observative characteristics that can be seen by the eye, also called phenotypes. Therefore, when a gene is mutated, the phenotype also changes. Besides, there are non-observative characteristics, which are alternation of the gene that are not visible by the human eye. Mutation for example organ failures, diabetes, or heart defects.
Mutations are commonly experienced as something that should not occur. However, there are multiple outcomes at alternations of DNA, the mutation did not express in a coding region, and therefore no phenotypical changes are witnessed. The alternation has taken place in an active coding region, and subsequently effecting the phenotype of an organism. These are the most common interpretations of DNA alternations.
Implementations of DNA alternations
Implementations of DNA mutations is commonly used in modern society. DNA mutation can be used as genetic markers for the identification of genetic variation, hereditary carriers and dominant inherent. Genetic variation in animals is experienced in everyday life, since every animal has a unique genotype that encodes for a unique phenotype that can be seen. Heredity carriers are more scientifically substantiated as where in the phenotype is not visible by the human eye. In general, the terms recessive and dominant are mostly used. Recessive means the organism has inherited the recessive allele (certain region of DNA) and dominant indicates the organisms has inherited the dominant allele.
The Hereditary carrier
The hereditary carrier is an organism which has inherited a recessive allele for a specific trait, but generally does not express the trait. Although the trait is not expressed by the organism, the organism is able to pass the allele on to the next generation. This way, a specific mutation can be present in multiple generations without noticing. Another possibility is in which the organisms have a dominant inherited allele. When an organism has a dominant and recessive allele for a specific allele, the dominant allele will be expressed. Nevertheless, if a hereditary carrier inherits a recessive allele for the specific trait it carries. This will result in the expression of the inhibited trait.
The well-known Punnet Square identifies the percentual change of an organism to be homozygote dominant (AA), homozygote recessive (aa) or heterozygote (Aa) (Edwards, 2012). If both parents are carriers and heterozygote the outcome would be 25% homozygote, 25% homozygote and 50% heterozygote. Resulting an allele mutation on the dominate allele would lead to 75% expression on the next generation. However, if the allele mutation was on the recessive allele only 25% of the next generation would express the recessive allele. In addition, spontaneous alternations can also cause genetic variation on alleles, and therefore lead to unexpected results. As for example the Punnet square is used to determine the percentual chance of the lineages genotype. A spontaneous alternation can change a phenotype, for example the hair colour. The linage can have different phenotypes then the ancestors if the breeding continues with the mutation.
Alleles are specific regions on the chromosome of an organism. The chromosome can be visualized using the technique karyotyping. During karyotyping all the chromosomes are coloured, and subsequently counted and examined using a microscope. Malfunctions in the chromosome assembly can be identified as irregularity of chromosomes or sometimes the number of chromosomes can be reduced or increased. Karyotyping is one of VHLGenetics genotyping techniques.
VHLGenetics DNA testing is performed at two laboratories. The head office is in Wageningen, the other laboratory is in Germany. DNA tests are performed under various accreditations, certifications, and memberships of organizations such as ICAR and IS. The main goal of VHLGenetics is to provide optimal DNA services for their customers. The core competence is the standardization of work processes in the laboratories. This while remaining flexibility in adding new tests and technologies to the portfolio. The DNA services have been developed from knowledge and experience gained in the last 30 years. DNA services are offered in a wide variety including plants and animals. The service involves mainly KASP, real-time PCR, capillary electrophoresis, and Thermo Fisher Scientific Targeted Genotyping by Sequencing®.