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Genome studies

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Schemat w formie różowych czworokątów przestawia sposób sekwencjonowania DNA. W górnym czworokącie znajduje się obraz komórki i szara, długa nić jej DNA. Poniżej kolorowe krótkie nici oznaczają pocięcie fragmentu DNA na małe odcinki. Strzałka prowadzi do prostokąta z zapisem odczytanej sekwencji nukleotydów. Niektóre fragmenty są w kolorach: różowym, zielonym i niebieskim. Na kolejnym etapie fragmenty są składane w jedną sekwencję. Ciemniejszy kolor oznacza identyczne odcinki. Ostatni czworokąt przedstawia zapis uzyskanej w ten sposób sekwencji DNA. Podpisano: isolating DNA from a cell; DNA is cut into short fragments; The nucleic acid sequence is determined in the short fragments; The fragments are put together into a complete sequence with bioinformatic tools

DNA sequencingDNA sequencingDNA sequencing is a laboratory technique that plays a crucial part in genetic research, enabling for precise determination of the order of nucleotides—adenine, guanine, thymine, and cytosine—that constitute the genetic code: unique data and guidelines on cell structure and functioning.

Discovering the coding sequences is immensely significant as the functions of specific genes can be determined this way. DNA sequencing is one of the fastest and cheapest methods of understanding the genotype.

The Human Genome Project

The Human Genome ProjectHuman Genome ProjectHuman Genome Project (HGP) was launched in 1990, with the aim to determine the entire sequence of the human genomegenomegenome and create maps of all chromosomes. The project was sponsored by the US Department of Energy and the National Institutes of Health.

The results have proved that:

• there are around 30,000 human genes, which is less than previously estimated;

• 90% of a DNA strand and DNA strand is so‑called, non‑coding DNA—or contains information undiscovered as of yet;

• a genome is composed of more than 3 billion nucleotide pairs;

• some genetic information is coded RNA, which can carry out many biochemical reactions in organisms;

• our knowledge of the human genome is still poor; it does not resemble a simple recipe for protein formation but rather a complex computer program.

The knowledge obtained from the project will contribute to the development more effective methods of diagnosing genetic diseases and detecting the risk of their occurrence, and perhaps of preventing some of them. The HGP also enabled the link between specific DNA sequences and skills and abilities to be proved, and helped discover new techniques of determining genetic sequences.

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Fotografia przedstawia wizualizację rozmiaru informacji, jakie zawiera ludzki genom. Pełna sekwencja ludzkiego genomu zajmuje kilkadziesiąt tomów, które są umieszczone na ośmiu półkach regału wysokiego po sufit. Na jednej z półek zaprezentowano otwarty wolumin, którego strony są gęsto pokryte bardzo drobno zapisanym tekstem opisującym ludzki genom.

Phylogenetic application of bioinformatics

PhylogeneticsphylogeneticsPhylogenetics is a subset of evolutionary biology concerned with determining the origin of organisms. Until recently, the origins of and relationships between organisms, also those that are extinct, used to be determined chiefly based on their structural, developmental, and functional similarities. Now, with databases of genetic sequences of many organisms (RNA and DNA sequences) and protein structures as well as advanced bioinformatic tools, the process of describing the history of the living world is both easier and more reliable.

The results of molecular research can sometimes contradict data collected by the anatomists. Differences in evaluating the validity of results obtained using traditional and bioinformatic methods have caused a divide in the scientific community.

Currently the most popular opinion says that it is indeed molecular research that both provides the most reliable results and is easier to carry out. They also enable for more remains to be studied. Anatomists often need bones or other well‑preserved body parts, preferably intact, while just the DNA is enough for genetic testing, and can be acquired from small fragments that are useless to anatomists. The isolated DNA is sequenced, and the strands obtained this way are then compared with the DNA of other organisms. If the similarity is significant, the organisms are closely related. This method also allows for comparing RNA and proteins of different organisms.

DNA barcoding

A barcode is a common sight in a shop, where it serves to identify items in a database. An analogous function for organisms is performed by the genetic sequence, a unique identifier of every living creature. By determining the sequence of nucleotides, the species of any given specimen can be determined with absolute certainty. Ideas have already been proposed and first attempts made to create a library of the genetic code of all organisms.

The Barcode of Life Data System (BOLD) is already in place. In 2005, it comprised 33,000 barcodesDNA barcodingbarcodes (DNA markers) for 12,700 species. Within eight years, the database grew to more than 2.6 million markers for approximately 190,000 species. Each of them includes the species name, code sequence, date and place of finding the specimen, photographs and other information.

Summary

• Modern phylogenetics uses the methods of molecular biology.

• Every organism has its own unique identifier:the nucleotide sequence.

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Keywords

DNA sequencing, Human Genome Project (HGP), phylogenetics

Glossary