Which event is represented by the above diagram related to chromosomal aberrations

Chromosomal aberration, or chromosomal mutation, is a missing, extra, or irregular portion of chromosomal DNA. These can occur in the form of numerical abnormalities (gains and losses) or structural abnormalities (deletions, inversions, and exchanges). Generally, chromosomal aberrations are going to be deleterious and lead to many genetic diseases. Numerical abnormalities can result in spontaneous abortions and severe birth defects. Structural abnormalities can lead to birth defects, cancer, and other late onset disease outcomes. Duplication Duplication mutation is gene sequence that is repeated several to hundreds of times. It can occur in normal chromosomes and may have adaptive advantages in fact. For example, useful mutations may occur in the copy of the original gene. Basically, the original gene provides a stable fallback, like a safety net, and the new gene can have mutations, like an experiment to express extra protein. Sometimes, the person who has duplication mutations can be completely unaffected. Deletion Deletion mutation results in the loss of some segment of a chromosome. Now, most deletion mutations are either lethal or will tend to cause serious disorders unlike the duplication mutation. For example, a disease called cri-du-chat is caused by the deletion mutation in the upper arm of chromosome 5. The deletion can lead to mental retardation and malformed larynx as well as obvious physical appearances. Inversion Inversion mutation is a chromosome rearrangeme...

An Introduction to Chromosomal Aberrations John R K Savage March 1999 (MRC Radiation and Genome Stability Unit, Harwell, Didcot, OX11 0RD, UK) Introduction Visible changes to chromosome structure and morphology have played a very important part as indicators of genetic damage in both clinical and cancer studies. Most of the changes encountered in clinical studies are "secondary" or "derived" aberrations. This is true also in cancer studies, except that here, there is an ongoing production of aberrations, so that in some cells, a mixture of primary and secondary changes is present, and a continuously changing karyotype ( true chromosomal instability). To appreciate these observed secondary changes we need to understand the primary changes from which they are derived, and it is the purpose of this article to provide a brief introduction to them. Observation Primary aberrations are those seen at the first post-induction division, when all the parts are present and there has been no selection by passage through mitosis, nor any modification by subsequent chromosome duplication (Savage, 1976). Most commonly, observation is made at metaphase, using "solid-staining" with dyes which give high-contrast chromatin staining and negligible cytoplasmic coloration. For more critical work, the chromosomes are banded in various ways, which allows chromosome identification, detection of some forms invisible with solid-staining, and offers more precise positioning of the lesion interaction p...

Genome instability, i.e., the tendency of the genome to undergo alterations in DNA information content through mutation, is considered a hallmark of aging. While mutations can be analyzed in clonal lineages, such as tumors, normal tissues have thus far not been amenable to mutation analysis except for the largest type of mutations: chromosomal aberrations. This is because mutations are random events and, therefore, unique to a single cell. New, single-cell sequencing-based methods are now emerging and may soon provide quantitative assays for estimating the possible functional effects of mutations accumulating during aging in various tissues and organs. Here we briefly review the mechanisms of genome instability in normal cells, the accumulation of various types of genome instability with age and their possible physiological consequences. • Previous article in issue • Next article in issue

Genome instability, i.e., the tendency of the genome to undergo alterations in DNA information content through mutation, is considered a hallmark of aging. While mutations can be analyzed in clonal lineages, such as tumors, normal tissues have thus far not been amenable to mutation analysis except for the largest type of mutations: chromosomal aberrations. This is because mutations are random events and, therefore, unique to a single cell. New, single-cell sequencing-based methods are now emerging and may soon provide quantitative assays for estimating the possible functional effects of mutations accumulating during aging in various tissues and organs. Here we briefly review the mechanisms of genome instability in normal cells, the accumulation of various types of genome instability with age and their possible physiological consequences. • Previous article in issue • Next article in issue

Chromosomal aberration, or chromosomal mutation, is a missing, extra, or irregular portion of chromosomal DNA. These can occur in the form of numerical abnormalities (gains and losses) or structural abnormalities (deletions, inversions, and exchanges). Generally, chromosomal aberrations are going to be deleterious and lead to many genetic diseases. Numerical abnormalities can result in spontaneous abortions and severe birth defects. Structural abnormalities can lead to birth defects, cancer, and other late onset disease outcomes. Duplication Duplication mutation is gene sequence that is repeated several to hundreds of times. It can occur in normal chromosomes and may have adaptive advantages in fact. For example, useful mutations may occur in the copy of the original gene. Basically, the original gene provides a stable fallback, like a safety net, and the new gene can have mutations, like an experiment to express extra protein. Sometimes, the person who has duplication mutations can be completely unaffected. Deletion Deletion mutation results in the loss of some segment of a chromosome. Now, most deletion mutations are either lethal or will tend to cause serious disorders unlike the duplication mutation. For example, a disease called cri-du-chat is caused by the deletion mutation in the upper arm of chromosome 5. The deletion can lead to mental retardation and malformed larynx as well as obvious physical appearances. Inversion Inversion mutation is a chromosome rearrangeme...

An Introduction to Chromosomal Aberrations John R K Savage March 1999 (MRC Radiation and Genome Stability Unit, Harwell, Didcot, OX11 0RD, UK) Introduction Visible changes to chromosome structure and morphology have played a very important part as indicators of genetic damage in both clinical and cancer studies. Most of the changes encountered in clinical studies are "secondary" or "derived" aberrations. This is true also in cancer studies, except that here, there is an ongoing production of aberrations, so that in some cells, a mixture of primary and secondary changes is present, and a continuously changing karyotype ( true chromosomal instability). To appreciate these observed secondary changes we need to understand the primary changes from which they are derived, and it is the purpose of this article to provide a brief introduction to them. Observation Primary aberrations are those seen at the first post-induction division, when all the parts are present and there has been no selection by passage through mitosis, nor any modification by subsequent chromosome duplication (Savage, 1976). Most commonly, observation is made at metaphase, using "solid-staining" with dyes which give high-contrast chromatin staining and negligible cytoplasmic coloration. For more critical work, the chromosomes are banded in various ways, which allows chromosome identification, detection of some forms invisible with solid-staining, and offers more precise positioning of the lesion interaction p...

An Introduction to Chromosomal Aberrations John R K Savage March 1999 (MRC Radiation and Genome Stability Unit, Harwell, Didcot, OX11 0RD, UK) Introduction Visible changes to chromosome structure and morphology have played a very important part as indicators of genetic damage in both clinical and cancer studies. Most of the changes encountered in clinical studies are "secondary" or "derived" aberrations. This is true also in cancer studies, except that here, there is an ongoing production of aberrations, so that in some cells, a mixture of primary and secondary changes is present, and a continuously changing karyotype ( true chromosomal instability). To appreciate these observed secondary changes we need to understand the primary changes from which they are derived, and it is the purpose of this article to provide a brief introduction to them. Observation Primary aberrations are those seen at the first post-induction division, when all the parts are present and there has been no selection by passage through mitosis, nor any modification by subsequent chromosome duplication (Savage, 1976). Most commonly, observation is made at metaphase, using "solid-staining" with dyes which give high-contrast chromatin staining and negligible cytoplasmic coloration. For more critical work, the chromosomes are banded in various ways, which allows chromosome identification, detection of some forms invisible with solid-staining, and offers more precise positioning of the lesion interaction p...

Chromosomal aberration, or chromosomal mutation, is a missing, extra, or irregular portion of chromosomal DNA. These can occur in the form of numerical abnormalities (gains and losses) or structural abnormalities (deletions, inversions, and exchanges). Generally, chromosomal aberrations are going to be deleterious and lead to many genetic diseases. Numerical abnormalities can result in spontaneous abortions and severe birth defects. Structural abnormalities can lead to birth defects, cancer, and other late onset disease outcomes. Duplication Duplication mutation is gene sequence that is repeated several to hundreds of times. It can occur in normal chromosomes and may have adaptive advantages in fact. For example, useful mutations may occur in the copy of the original gene. Basically, the original gene provides a stable fallback, like a safety net, and the new gene can have mutations, like an experiment to express extra protein. Sometimes, the person who has duplication mutations can be completely unaffected. Deletion Deletion mutation results in the loss of some segment of a chromosome. Now, most deletion mutations are either lethal or will tend to cause serious disorders unlike the duplication mutation. For example, a disease called cri-du-chat is caused by the deletion mutation in the upper arm of chromosome 5. The deletion can lead to mental retardation and malformed larynx as well as obvious physical appearances. Inversion Inversion mutation is a chromosome rearrangeme...

Genome instability, i.e., the tendency of the genome to undergo alterations in DNA information content through mutation, is considered a hallmark of aging. While mutations can be analyzed in clonal lineages, such as tumors, normal tissues have thus far not been amenable to mutation analysis except for the largest type of mutations: chromosomal aberrations. This is because mutations are random events and, therefore, unique to a single cell. New, single-cell sequencing-based methods are now emerging and may soon provide quantitative assays for estimating the possible functional effects of mutations accumulating during aging in various tissues and organs. Here we briefly review the mechanisms of genome instability in normal cells, the accumulation of various types of genome instability with age and their possible physiological consequences. • Previous article in issue • Next article in issue

Genome instability, i.e., the tendency of the genome to undergo alterations in DNA information content through mutation, is considered a hallmark of aging. While mutations can be analyzed in clonal lineages, such as tumors, normal tissues have thus far not been amenable to mutation analysis except for the largest type of mutations: chromosomal aberrations. This is because mutations are random events and, therefore, unique to a single cell. New, single-cell sequencing-based methods are now emerging and may soon provide quantitative assays for estimating the possible functional effects of mutations accumulating during aging in various tissues and organs. Here we briefly review the mechanisms of genome instability in normal cells, the accumulation of various types of genome instability with age and their possible physiological consequences. • Previous article in issue • Next article in issue