Name: genome variation in cnvs and snps
Uploaded: 2021-04-07T12:11:59.000Z
Duration: 2 min 26 s
Channel: JoVE

K12 Standards

Louisiana Student Standards for Science

High School

Life Sciences

Biological Evolution: Unity And Diversity

HS-LS4-1

comparing-copy-number-variations-and-snps

Comparing Copy Number Variations and SNPs

Genomische Variationen wie das Hinzufügen oder Löschen von DNA-Segmenten werden häufig in einer Population beobachtet. Genomische Variationen in einer Population können durch Einzelnukleotidveränderungen in der DNA oder strukturelle Veränderungen der Chromosomen entstehen.
Kopienzahlvariation oder CNV ist ein Überbegriff, der die strukturellen Variationen definiert, an denen DNA-Segmente von mehr als 1 Kilo Basenpaar beteiligt sind.
Wenn das beteiligte Chromosomensegment ein Gen enthält, können die CNVs die Kopienzahl dieses Gens durch Duplikation und Insertion erhöhen oder durch Deletion verringern, was zu einem Null-Genotyp führt.
Daher können einige Individuen zwei oder sogar mehr Kopien eines Gens oder gar keine Kopien haben. Zum Beispiel können einige Menschen europäischer genetischer Abstammung zwei Kopien des Rhesus-Blutgruppen-Gens RHD tragen, während andere nur eine und andere überhaupt keine haben.  
CNV kann die Phänotypen beeinflussen, die von der Anzahl der funktionellen Genkopien abhängen. In europäisch-amerikanischen und asiatischen Regionen, in denen stärkebasierte Diäten üblich sind, weist die Population eine höhere Kopienzahl des Gens AMY1 auf, eines Gens, das am Stärkestoffwechsel beteiligt ist.
CNVs werden auch mit verschiedenen Krankheiten wie Psoriasis, Parkinson und Verhaltensstörungen wie Autismus und Schizophrenie in Verbindung gebracht.
Während CNVs in der Regel große Variationen der DNA-Sequenz abdecken, handelt es sich bei Einzelnukleotid-Polymorphismen oder SNPs um zufällige Einzelbasensubstitutionen, die im gesamten Genom vorkommen.
Solche Basensubstitutionen treten einmal alle 1000 Nukleotide auf; nicht alle von ihnen qualifizieren sich jedoch als SNPs. Im Allgemeinen wird nur eine Nukleotidvariation, die bei mehr als 1% der Bevölkerung vorkommt, als SNP bezeichnet.
SNPs können verschiedene Krankheiten wie Diabetes oder Krebs übertragen. Bei Patienten mit Sichelzellenanämie führt beispielsweise eine einzelne Basensubstitution von Adenin zu Thymin an einem bestimmten Ort des Beta-Globin-Gens zu sichelförmigen roten Blutkörperchen.

<ol>
	<li>Lee, Charles und Stephen W. Scherer. "Der klinische Kontext der Variation der Kopienzahl im menschlichen Genom." Expertenbewertungen in der Molekularmedizin 12 (2010).</li>
	<li>Budowle, Bruce und Angela Van Daal. "Forensisch relevante SNP-Klassen." Biotechniques 44, Nr. 5 (2008): 603-610.</li>
</ol>

vergleich von kopienzahlvariationen und snps

Die Sequenzierung des menschlichen Genoms hat einige der bestgehüteten Geheimnisse des Genoms aufgedeckt. Wissenschaftler haben Tausende von Genomvariationen identifiziert, die innerhalb einer Population existieren. Diese Variationen können ein einzelnes Nukleotid oder eine größere chromosomale Variation sein.

Kopienzahlvariationen oder CNVs sind strukturelle Variationen, die mehr als 1 kb der DNA-Sequenz abdecken. Die Einzelnukleotid-Polymorphismen (SNP) hingegen sind einzelne Nukleotidänderungen oder Punktmutationen, die bei mehr als 1% der Bevölkerung zu finden sind. Sowohl CNVs als auch SNPs sind von immensem Wert in genetischen Screening-Studien und Verwandtschaftsanalysen.

Formen von CNVs

Es gibt fünf Formen von CNVs. Die erste wird als Deletion bezeichnet. Ein Verlust eines DNA-Segments kann die Kopienzahl eines Gens oder einer Gruppe von Genen verringern. Die zweite wird als Tandemduplikation bezeichnet. Hier wird eine Kopie eines chromosomalen Segments in eine angrenzende Region eingefügt. Die dritte wird als nicht benachbarte Duplikation bezeichnet. Hier dupliziert sich ein chromosomales Segment und wird in eine entfernte chromosomale Region oder ein anderes Chromosom eingefügt. Die vierte Form wird als multiallelische CNV bezeichnet. Ein DNA-Segment dupliziert sich mehrmals und führt zur Bildung mehrerer Allele eines Gens. Die fünfte Form wird als komplexe Umordnung bezeichnet. Hier wird ein DNA-Segment dupliziert und invertiert, bevor es zurück in dasselbe oder ein anderes Chromosom eingefügt wird.

Einzelnukleotid-Polymorphismus

Der Einzelnukleotid-Polymorphismus oder SNP ist eine weitere Art von genomischer Variation, die Veränderungen in einem einzelnen Nukleotidbase beinhaltet. Wissenschaftler haben Tausende von SNPs im gesamten menschlichen Genom identifiziert, und sie werden routinemäßig als genetische Marker für erbliche Krankheiten und forensische Analysen verwendet.

Basierend auf ihrer Anwendung werden SNPs in vier Typen unterteilt. Identitätsprüfende SNPs werden verwendet, um Menschen zu differenzieren und Personen von familiären Verbindungen auszuschließen. Abstammungsinformative SNPs sind eng verknüpfte SNPs, die helfen, vermisste Personen in einer familiären Analyse zu identifizieren. Abstammungsinformative SNPs helfen, die Abstammung einer Person zu bestimmen und sie mit ihren phänotypischen Merkmalen zu verbinden. Phänotypinformative SNPs stellen die Wahrscheinlichkeit fest, einen bestimmten Phänotyp zu erben, wie Hautfarbe, Augenfarbe usw.

Vergleich von Kopienzahlvariationen und SNPs

Die Sequenzierung des menschlichen Genoms hat mehrere bestgehütete Geheimnisse des Genoms enthüllt. Wissenschaftler haben Tausende von Genomvariationen identifiziert, die es gibt ...

Education

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JoVE Core

Molecular Biology

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Einheit 2

Genomes and Evolution

Genome und Evolution

KEY TERMS AND CONCEPTS

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genome variation in cnvs and snps

Genome variation in CNVs and SNPs shows how DNA can differ across people in a population. These differences may involve a single nucleotide, which is one DNA base, or a larger chromosomal change. Scientists study them to understand inherited variation in the human genome.

Copy number variations, or CNVs, are structural changes that cover more than 1 kb of DNA sequence. A CNV can change the number of copies of a gene or a group of genes. The main forms are deletion, tandem duplication, noncontiguous duplication, multiallelic CNV, and complex rearrangement.

A deletion removes a DNA segment and can lower gene copy number. In tandem duplication, a copied chromosomal segment is inserted next to the original region. In noncontiguous duplication, the copied segment moves to a distant chromosomal region or even a different chromosome. Multiallelic CNV creates several copies and can produce multiple alleles of a gene. In complex rearrangement, a segment duplicates and inverts before it is inserted back into the same or a different chromosome.

Single nucleotide polymorphism, or SNP, is another genomic variation that changes one nucleotide base. A SNP is a point mutation found in more than 1% of the population. Scientists have identified thousands of SNPs across the human genome, and they are widely used as genetic markers in studies of inherited disease and forensic analysis.

SNPs are grouped by use into four types. Identity-testing SNPs help distinguish people and exclude familial connections. Lineage informative SNPs are tightly linked SNPs that help identify missing individuals in family analysis. Ancestry informative SNPs help connect a person's ancestry with related phenotypic traits. Phenotype informative SNPs help estimate the chance of traits such as skin color or eye color.

Genome Variation in CNVs and SNPs

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comparing copy number variations and snps

Genome variation in CNVs and SNPs shows how DNA can differ across people in a population. These differences may involve a single nucleotide, which is one DNA base, or a larger chromosomal change. Scientists study them to understand inherited variation in the human genome. Copy number variations, or CNVs, are structural changes that cover more than 1 kb of DNA sequence. A CNV can change the number of copies of a gene or a group of genes. The main forms are deletion, tandem duplication,...

key terms and concepts

Explore how copy number variations and SNPs change the human genome, from deletions and duplications to ancestry, identity, and phenotype markers.

Genome Variation in CNVs and SNPs | JoVE K12

molecular biology

JoVE Core Molecular Biology veranschaulicht die molekularen Prozesse der Zelle in prägnanten animierten Video-Lektionen. In Videos von Wissenschaftlern in Aktion wird die Anwendung dieser Konzepte zusätzlich durch reale Experimente in modernen Laboren demonstriert.

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Ohio’s Learning Standards and Model Curriculum

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Biology

Evolution

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Virginia  Standards of Learning

HIgh School

BIO.5

BIO.5.d

Minnesota Academic Standards in Science

Life Science

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New Jersey Student Learning Standards for Science

Biological Evolution: Unity and Diversity

Arizona Science Standards

HS+B.L4

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HS-LS4-5

Genome Variation in CNVs and SNPs

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