Systematic And Molecular Evolution: Mitochondrial Dna

Systematic and molecular evolution: Mitochondrial DNA

Introduction

In this report we will talk about the systematic, which deals with classifying the known species of living beings from an evolutionary compression, molecular evolution aims to study or analysis of the variability that occurs in the DNA sequence inrelationship with the passage of time. Mitochondrial DNA or also known as mitochondrial genome, is that genetic material or a small circular chromosome that belongs to the mitochondria.

Mitochondria are subcellular orn membrane ornaulus that is practically found in all eukaryotic cells, these contain multiple molecules which synthesize, such as DNA, RNA and all proteins it encodes, it should be emphasized that the mitochondrial heritage is characterized by aexclusively maternal transmission is also known as matrilineal ancestry. Reference should be made to cytoplasmic inheritance, which is responsible for the transfer of genes present in the cell cytoplasm that are not linked to the cromosomes of the nucleus. This type of inheritance is also known as foreign inheritance and is part of the different hereditary patterns known as non-methodos.

Developing

Systematic and molecular evolution

We understand in a broad sense by evolution to the changes that occur in the characteristics of each organism with the passage of time, taking into account that the current complexity of the metabolic routes was not such in its origins. When we talk about molecular evolution we refer to the evolution of molecules and specifically talk about nucleic acids that constitute hereditary material (genes) and proteins that are the primary product of these genes.

(Science, 2017)

• Molecular level adaptation and natural selection

Purifying selection eliminates those mutations that spoil existing adaptations, whether at the molecular level or at other levels. Positive natural selection is the only evolutionary force that can explain the new adaptations. (Science, 2017)

Molecular systematic uses the genetic information of nucleic acids and RNAs fundamentally to deduce kinship relationships between organisms. If the characteristics or variations are shared between two organisms, it is understood that they are related. (Molina, 2014)

DNA is found in eukaryotes, in the nucleus, mitochondria and chloroplasts, their inheritance is different:

• Nuclear DNA: It is normally inherited biparental, DNA is used that encodes Ribosomal RNA.
• Mitochondrial and chloroplastidial DNA: it is inherited only by one of the parents, usually by the mother, since these organelles are often transferred through the ovules. (Molina, 2014)

Mitochondrial DNA

What is?

It is the genetic material located in the mitochondria, these organelles are responsible for producing energy in the form of ATP. ADNMT is a small chromosome and maintains the shape of a circle.

Endosimbiotic theory

It establishes that 2 billion years ago, before being considered the mitochondria as a cell organelle was a free bacterium that was in the ocean. It was a bacterium that was developed in the presence of oxygen present in the medium (aerobic) using it to obtain the necessary energy to stay alive. At a certain moment this bacteria was "devoured" by a cell which contained a nucleus and lived in anaerobic conditions. However, the cell did not digest the bacteria but a symbiosis relationship was established, that is, they were associated in order to benefit each other in their vital development. The eukaryotic cell allowed the oxygen passage so that the mitochondria would capture it and the mitochondria contributed producing energy (ATP) for the eukaryotic cell.

CHARACTERISTICS OF ADNMT

1. ADNMT is inherited from the mother: the nuclear DNA contains genetic information of the parents, however, the ADNMT acquires genetic information only by the mother. The DNAmt is inherited from the mother, this because in fertilization when the sperm enters the ovule, its tail next to its mitochondria are destroyed due to the defense system that the ovule has, therefore the formation of the zygote onlyIt would be influenced by the mitochondria containing the ovule.
2. High mutation rate: its mutation rate is 10-17 times greater than that of the nuclear DNA because the DNMT has greater vulnerability against free radicals that are generated in oxidative metabolism due to lack of protection by not being surrounded by histones.
3. Polylasmia: Refers to the colossal number of CPNMT copies present in each mitochondria. Within this organelle in ADNMT it is linked to certain binding proteins, forming a nucleoid. These structures are found in a 2-10 portion in each mitochondria, so the amount of DNMT copies in each cell is between one thousand and ten thousand.

ADNMT uses

• It serves for the identification of people based on another evidence.
• In the forensic area it serves to identify samples of human skeletons.
• It serves to find relationship between a group of people, it is used to compare the DNM between missing individuals or remains that have not been identified and their relatives.
• It serves to study relationships in the evolutionary aspect, since DNAmt is extracted in greater quantity than nuclear DNA thanks to the large number of such organelles (mitochondria) present in the cell. ADNMT intact from generation to generation except in case there is a mutation.

Mitochondrial DNA Structure

Human mitochondrial DNA is a closed duplohelicoidal molecule with double strand as the bacterial genome consisting of 16.569 base pairs whose sequence is known in its entirety. This DNA encodes 37 genes that correspond to two ribosomal RNAs (RARN) components of the mitochondrial ribosomes, 22 transfer arns (tarns), and 13 component polypeptides of the respiratory complexes of the mitochondrial internal membrane.

The DNA heavy chain (h) encodes the 2 rarns, 14 tarns and 12 polypeptides, while the light chain (l) only contains information for 8 tarns and a polypeptide, the genes, in the heavy chain, one is arranged below one belowon the other, without intermediate coding sections. One of the most surprising characteristics of mitochondrial DNA is that it presents an extremely compact genetic organization, another of the peculiarities of the genetic organization of mitochondrial DNA is the distribution of the tarns genes throughout the DNA sequence. In the heavy chain, these separate almost regularly the rare genes and protein encoders. This provision will have very important consequences for RNA processing.

Mitochondria contain multiple Mtadn molecules

The MTADN is in an area called matrix inside the mitochondria. In myitosis, daughter cells receive a similar number of mitochondria, despite this, since there is no mechanism to perform an exact division of the number of mitochondria for each daughter cell, there are cells that have more mtadn. If the mitochondria is isolated and the DNA present in them is studied, it is seen that each mitochondria has several DNA molecules. As a consequence, the total MTADN will depend on three factors, which vary depending on the cell type, these are: the number of mitochondria, the number of MTADN molecules in each mitochondria and the size of the Mtadn molecules. By microscopy by fluorescence, MTADN can be detected, in living cells the temporary sequence microscopy is used to observe the replication of the mitochondrial DNA and the division of the mitochondria, the dyes that are used do not interfere with the division and cell growth. As a result of these studies, it is known that Mtadn is replicated during the interface. (Harvey, 2006)

The MTADN has cytoplasmic heritage

Mitochondria present cytoplasmic heritage, because of this they contain their own genetic system. Several studies have shown that the MTADN is inherited from the mother, in the case of mammals, the ovules largely contribute the mitochondria that the embryo possesses, instead the spermcase of much of multicellular organisms. In higher plants, Mtadn’s inheritance occurs in a uniparental way, through the egg that is the female parent and not the pollen that is the masculine. The mtadn encodes rrna ytrna. Mitochondrial ribosomes synthesize the proteins encoded by MTADN, these proteins are transported to the interior of the mitochondria, since they are formed in cytoplasmic organelles, examples of these proteins are examples of the DNA polymerase rna. Mtadn mutations can cause various diseases, which depend on the type of mutation and how many mtadn has mutated, these mutations have greater impact on those tissues that need a greater contribution of ATP produced by oxidative phosphorylation and those who use everythingMTADN to synthesize functional mitochondrial proteins. (Feduchi, 2010)

Conclusions

We conclude by saying that systematic and molecular evolution allow us to understand genetic information, where we understand that when organisms share similar characteristics it follows that they are related. In addition, the understanding that DNAmT acquires genetic information only by the mother, but without leaving aside the nuclear DNA contains genetic information of the parents. Structurally, mitochondrial DNA is made up of a heavy chain (h) which encodes the 2 rarns, 14 tarns and 12 polypeptides, while the light chain (l) contains only information for 8 tarns and a polypeptide. Like the cytoplasmic inheritance of mitochondrial DNA, it allows us to transfer those genes that are in the cell cytoplasm that do not maintain a link with the cromosomes of the nucleus.