This activity will allow students to evaluate two patients with possible neurological symptoms. Students will come up with possible diagnosis and determine how to test for these diagnoses.
Methods of Flu Genome Sequencing Genome Sequencing Influenza viruses are constantly evolving, in fact all influenza viruses undergo genetic changes over time for more information, see How the Flu Virus Can Change: CDC conducts year-round surveillance of circulating influenza viruses to monitor changes to the genome or parts of the genome of these viruses.
This work is performed as part of routine U. Full Sized Infographic and Text Version Genome sequencing reveals the sequence of the nucleotides in a gene, like alphabet letters in words. Comparing the composition of nucleotides in one virus gene with the order of nucleotides in a different virus gene can reveal variations between the two viruses.
Proteins are made of sequences of amino acids.
The substitution of one amino acid for another can affect properties of a virus, such as how well a virus transmits between people, and how susceptible the virus is to antiviral drugs or current vaccines.
Influenza A and B viruses — the primary influenza viruses that infect people — are RNA viruses that have eight gene segments. Influenza genes consist of a sequence of molecules called nucleotides that bond together in a chain-like shape. Nucleotides are designated by the letters A, U, C or G.
Genome sequencing is a process that determines the order, or sequence, of the nucleotides i. Each year CDC performs whole genome sequencing on about 6, influenza viruses from original clinical samples collected through virologic surveillance.
Of the eight genes that make up an influenza A or B virus, CDC focuses on sequencing two gene segments: Genetic Characterization CDC and other public health laboratories around the world have been sequencing the genes of influenza viruses since the s.
The resulting libraries of gene sequences allow CDC and other laboratories to compare the genes of currently circulating influenza viruses with the genes of older influenza viruses and viruses used in vaccines. Through this process of comparing genetic sequences, called genetic characterization, CDC can make informed assumptions regarding: Each sequence from a specific influenza virus has its own branch on the tree.
The degree of genetic difference number of nucleotide differences between viruses is represented by the length of the horizontal lines branches in the phylogenetic tree.
The further apart viruses are on the horizontal axis of a phylogenetic tree, the more genetically different the viruses are to one another. As part of this process, CDC compares the new virus sequence with the other virus sequences, and looks for differences among them.
CDC then uses a phylogenetic tree to visually represent how genetically different the H3N2 viruses are from each other. CDC performs genetic characterization of influenza viruses year round. This genetic data is used in conjunction with virus antigenic characterization data to help determine which vaccine viruses should be chosen for the upcoming Northern Hemisphere or Southern Hemisphere influenza vaccines.
In the months leading up to the WHO vaccine consultation meetings in February and September, CDC collects influenza viruses through surveillance and compares the HA and NA gene sequences of current vaccine viruses against those of circulating flu viruses.
This is one way to assess how closely related the circulating influenza viruses are to the viruses the seasonal flu vaccine was formulated to protect against.
As viruses are collected and genetically characterized, differences can be revealed. For example, sometimes over the course of a season, circulating viruses will change genetically, which causes them to become distinctly different from the corresponding vaccine virus.
The HA and NA surface proteins of influenza viruses are antigens, which means they are recognized by the immune system and are capable of triggering an immune response, including production of antibodies that can block infection.
Methods of Flu Genome Sequencing One influenza sample contains many influenza virus particles that were grown in a test tube and that often have small genetic differences in comparison to one another among the whole population of sibling viruses. Sanger sequencing identifies the predominant genetic sequence among the many influenza viruses found in an isolate.
This means small variations in the population of viruses present in a sample are not reflected in the final result.
Therefore, NGS reveals the genetic variations among many different influenza virus particles in a single sample, and these methods also reveal the entire coding region of the genomes. This level of detail can directly benefit public health decision-making in important ways, but data must be carefully interpreted by highly-trained experts in the context of other available information.genetic material in many viruses.
13 THE STRUCTURE OF DNA AND RNA • The nucleotide is the repeating structural unit of DNA and RNA • It has three components – A phosphate group – A pentose sugar – A nitrogenous base Nucleotides.
14 Repeating unit comprised of: phoshategroup + pentose sugar + nitrogenous base. The virus injects its genetic material into the cell and uses the cell's organelles to replicate. Once a sufficient number of viruses have been replicated, the newly formed viruses lyse or break open the host cell and move on to infect other cells.
Mar 21, · A version of this article appears in print on March 21, , on Page A of the National edition with the headline: Genetic Material of Virus From Flu Is Found. Background Infection of poultry with influenza A subtype H7 viruses occurs worldwide, but the introduction of this subtype to humans in Asia has not been observed previously.
Scientists have long theorized that the herpes virus is so stuffed with genetic material that it explodes its genetic material straight out of its virus shell and right into its desired host. Genetics is the study of genes, genetic variation, and heredity in living organisms.
It is generally considered a field of biology, but intersects frequently with many other life sciences and is.