Name: chromosome rearrangements and synteny
Uploaded: 2021-04-07T12:11:59.000Z
Duration: 2 min 31 s
Channel: JoVE

K12 Standards

north-carolina-k-12-science-standard-course-of-study

NC K-12 Science Standard Course of Study

9-12

Biology

Biological Evolution- Unity and Diversity

LS.Bio.10.2

Synteny and Evolution

Synteny in classical terms refers to the genes present on the same chromosome, like beads on the same string.
For example, consider species X, which has genes A, B, and C present on one chromosome. These genes are said to be syntenic in species X.
Then consider another species, Y, with alleles A1, B1, and C1 on another chromosome. These genes are also said to be syntenic in species Y.
In evolutionary perspective, synteny refers to the phenomenon of co-localization of genes on a chromosome of two or more different species.
Therefore, the genes A and A1, B and B1 and C and C1 represent a synteny between the two species, X and Y.
In addition, the genes present in common chromosomal regions in two or more species, like the genes A, B and C, represent a conserved syntenic segment or conserved syntenic blocks.
During the course of evolution, species undergo random mutations, survive natural selection and evolve into several lineages all while mostly maintaining conserved syntenic blocks over many chromosomes.
For example, around 85 million years ago, humans and tree shrews shared a common mammalian ancestor. Even after millions of years of divergence, several genes present on the long ar

synteny and evolution

John H. Renwick first coined the term &#8220;synteny&#8221; in 1971, which refers to the genes present on the same chromosomes, even if they are not genetically linked. The species with common ancestry tend to show conserved syntenic regions. Therefore, the concept of synteny is nowadays used to describe the evolutionary relationship between species.
Around 80 million years ago, the human and mice lineages diverged from the common ancestor. During the course of evolution, the ancestral chromosome underwent several rearrangements, breakage, and fusion events to evolve into the chromosomes of mice and humans. For example, it took around 180 chromosomal breakage-and-rejoining events for the evolution of ancestral chromosomes into human and mice chromosomes. Yet, several regions of chromosomes in both mice and humans have maintained common gene order or synteny. For example, over 510,000 base pairs of mouse chromosome 12 share syntenic blocks with human chromosome 14. In the future, when&#160; the evolutionary distance between two species will increase, the number of chromosomal breakage-and-rejoining events will increase, and the synteny will decrease.
<h4>Primate ancestral karyotype</h4>
Based on synteny relation and DNA sequence analysis, scientists have predicted the karyotype of all primate ancestors. Synteny between humans and other primates such as chimpanzees, gorillas, and other living primate species reveals that human chromosomes are derived from ancestral chromosomes by several chromosomal breakage-and-rejoining events. Such large-scale chromosome rearrangements are rare, like once in 5 million years. But whenever they occur, they are most likely to lead to the evolution of a new species. A comparison between human chromosomes with the proposed primate ancestral karyotype shows several chromosome rearrangements. For example, the fusion of ancestral chromosomes 9 and 11 formed the human chromosome 2; or the reciprocal translocation of ancestral chromosomes 14 and 21 led to the evolution of human chromosomes 12 and 22.

John H. Renwick first coined the term &#8220;synteny&#8221; in 1971, which refers to the genes present on the same chromosomes, even if they are not ...

Education

JoVE Core

Molecular Biology

Unit 2

Genomes and Evolution

KEY TERMS AND CONCEPTS

chromosome rearrangements and synteny

Chromosome rearrangements and synteny show how shared gene order can reveal evolutionary history. Synteny means genes are found on the same chromosome, even if they are not genetically linked. John H. Renwick coined the term in 1971. Species with common ancestry often keep conserved syntenic regions.

Scientists use synteny to compare the evolutionary relationship between species. Human and mouse lineages split from a common ancestor about 80 million years ago. Since then, the ancestral chromosome has gone through breakage, rearrangement, and fusion events to become the chromosomes seen in humans and mice. It took about 180 chromosomal breakage-and-rejoining events to form the human and mouse chromosome sets.

Even with those changes, some chromosome regions still keep the same gene order. For example, more than 510,000 base pairs of mouse chromosome 12 share syntenic blocks with human chromosome 14. As the evolutionary distance between two species increases, the number of breakage-and-rejoining events tends to rise, and synteny tends to decrease.

Scientists also use synteny and DNA sequence analysis to predict the karyotype, or chromosome set, of primate ancestors. Human chromosomes show synteny with chimpanzees, gorillas, and other living primates, which suggests that human chromosomes came from ancestral chromosomes through several breakage-and-rejoining events. These large chromosome rearrangements are rare, occurring about once in 5 million years, but they can help drive the formation of new species.

A comparison with the proposed primate ancestral karyotype shows several specific rearrangements. The fusion of ancestral chromosomes 9 and 11 formed human chromosome 2. A reciprocal translocation between ancestral chromosomes 14 and 21 led to human chromosomes 12 and 22.

Chromosome Rearrangements and Synteny

evolutionary relationships through genome comparisons

evolutionary-relationships-through-genome-comparisons

Tracing Evolution with Genome Data

Genome data helps scientists trace how organisms are related over time. When two species share a common feature, it is often encoded by DNA sequences that have stayed conserved in both species. As genome sequencing improved in the late 20th century, researchers gained a better way to compare conserved domains across species and use that evidence to infer evolutionary relationships. Genome comparison can show evolutionary relationships at three levels. At the broadest level, it highlights...

genome copying errors

DNA Replication Error Checks

DNA replication includes built-in error checks that protect the genome during cell division. Even though this process copies millions of base pairs with high fidelity, a wrong base or a longer stretch of wrong bases can still be added to the daughter strands. If these mistakes are not corrected, cells may build up mutations that can threaten survival. One level of repair is proofreading. DNA polymerase enzymes, which build the new DNA strand, can make about 1 incorrect nucleotide per 100,000...

phylogenetic trees

Reading Evolution in Phylogenetic Trees

Phylogenetic trees show how organisms are related through evolution. They map branching patterns that trace common ancestry and help scientists compare species over time. A phylogenetic tree can be read like a family tree for life. Each branch point marks a split from a shared ancestor, and the pattern of branches shows how closely related different organisms are. These trees are used to organize biological information and to study evolutionary change. They can also help scientists understand...

Chromosome rearrangements and synteny show how shared gene order can reveal evolutionary history. Synteny means genes are found on the same chromosome, even if they are not genetically linked. John H. Renwick coined the term in 1971. Species with common ancestry often keep conserved syntenic regions. Scientists use synteny to compare the evolutionary relationship between species. Human and mouse lineages split from a common ancestor about 80 million years ago. Since then, the ancestral...

multi-species conserved sequences

Conserved DNA Across Species

Conserved DNA across species shows how some genome regions stay nearly unchanged over time. Next-generation sequencing has built large genome databases for many animals and plants. Since the Human Genome Project, scientists have compared the genomes of primates, mammals, and other distant species. These large studies have helped reveal evolutionary relationships between organisms. Although species genomes differ greatly, a few DNA sequences are highly conserved. Conserved DNA sequences found...

gene duplication and divergence

How Duplicate Genes Shape Evolution

Gene duplication helps drive evolution by creating extra copies of DNA that can change over time. The seminal work of Ohno in 1970 helped popularize this idea. DNA sequence comparisons show that many genes in bacteria, archaebacteria, and eukaryotes came from duplication and later divergence, which makes this process important in evolution. The duplicated copies of a gene are called paralogs. When paralogs have similar sequences and functions, they form a gene family. Many gene families have...

exon recombination

How Exons Mix to Form New Genes

Exon recombination helps new genes form by mixing exons from the same gene or from different genes. This process is also called exon shuffling or domain shuffling. It has been seen in vertebrates, invertebrates, and some plants, including potatoes and sunflowers. During exon recombination, exons join in new exon-intron combinations. These new combinations may later become new genes. Exon shuffling follows splice frame rules, which means the exons must fit the reading frame correctly. Each...

comparing copy number variations and snps

comparing-copy-number-variations-and-snps

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,...

key terms and concepts

Explore how synteny reveals chromosome rearrangements, shared gene order, and primate ancestry through human, mouse, and other primate examples.

Chromosome Rearrangements and Synteny | JoVE K12

molecular biology

JoVE Core Molecular Biology showcases the molecular processes of the cell through clear and concise animated video lessons. Additionally, in scientist-in-action videos, these concepts' application is demonstrated through real experiments in modern laboratories.

ohios-learning-standards-and-model-curriculum

Ohio’s Learning Standards and Model Curriculum

Evolution

Speciation

Minnesota Academic Standards in Science

Life Science

3.2.1 9L.3.2.1.3

new-jersey-student-learning-standards-for-science

New Jersey Student Learning Standards for Science

High School

Biological Evolution: Unity and Diversity

HS-LS4-1

Arizona Science Standards

HS+B.L4

HS+B.L4U1.13

Alabama Course of Study Science

Unity and Diversity

9-12.B.4.13

Next Generation Science Standards

heredity-inheritance-and-variation-of-traits

Heredity: Inheritance and Variation of Traits

south-carolina-college-and-career-ready-science-standards

South Carolina College and Career Ready Science Standards

B-LS4-1.

new-york-state-science-learning-standards

New York State Science Learning Standards

Natural Selection and Evolution

HS-LS4-1.

Development of Antibiotic Resistance

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Understanding Species and Reproductive Barriers

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Formation of Species

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Speciation Rates

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Hybrid Zones

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What is Natural Selection?

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Types of Selection

Natural selection influences the frequencies of particular alleles and phenotypes within populations in several different ways. Primarily, natural ...

Frequency-dependent Selection

When the fitness of a trait is influenced by how common it is (i.e., its frequency) relative to different traits within a population, this is referred to ...

Limits to Natural Selection

Organisms that are well-adapted to their environment are more likely to survive and reproduce. However, natural selection does not lead to perfectly ...

Natural Selection

Fitness
Widespread variation of phenotypes in natural populations provides the raw material for evolution, which is the change in the inherited traits of ...

Simulating Natural Selection
ExpandTo prepare for the lab, set out workstations for each student pair containing 6 white, 6 black, and 13 gray 12 inch ...

Simulating Natural Selection
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Artificial Selection

Natural Selection and Adaptive Evolution
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Observing Artificial Selection in Plants
ExpandTwo weeks before beginning the pollination experiments, collect a sufficient amount of small pots with a ...

Observing Artificial Selection in Plants 
ExpandTo begin the experiment, collect five two-week old grown plants from the generation one population that ...

Analyze and interpret data to summarize how various factors such as geographic isolation, pesticide resistance, antibiotic resistance can influence natural selection.

LS.Bio.9.1

Phylogenetic Trees

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Conditions on Early Earth

Around 4 billion years ago, oceans began to condense on earth while volcanic eruptions released nitrogen, carbon dioxide, methane, ammonia, and hydrogen ...

The Colonization of Land

Changes in the environment of the early Earth drove the evolution of organisms. As prokaryotic organisms in the oceans began to photosynthesize, they ...

What is Evolutionary History?

Scientists record evolutionary history by analyzing fossil, morphological, and genetic data. The fossil record documents the history of life on Earth and ...

The Evidence for Evolution

Genetic variations accumulating within populations over generations give rise to biological evolution. Evolutionary changes can result in the formation of ...

The Fossil Record

The fossil record documents only a small fraction of all organisms that have ever inhabited Earth. Fossilization is a rare process, and most organisms ...

Convergent Evolution

Evolution shapes the features of organisms over time, ensuring that they are suited for the environments in which they live. Sometimes, selection pressure ...

Gene Evolution - Fast or Slow?

The genomes of eukaryotes are punctuated by long stretches of sequence which do not code for proteins or RNAs. Although some of these regions do contain ...

genome-size-and-the-evolution-of-new-genes

Genome Size and the Evolution of New Genes

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Gene Families

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types-of-genetic-transfer-between-organisms

Types of Genetic Transfer Between Organisms

Genetic transfer occurs when genetic information is passed from one organism to another. It occurs via two mechanisms: vertical gene transfer and ...

Ribozymes

The term ribozyme is used for RNA that can act as an enzyme. Ribozymes are mainly found in selected viruses, bacteria, plant organelles, and lower ...

Construct an explanation to illustrate how common ancestry and biological evolution are supported by multiple lines of empirical evidence.

LS.Bio.9.2

Use models to illustrate the conditions required for natural selection, including the overproduction of offspring, inherited variation, and the struggle to survive.

LS.Bio.9.3

Construct an explanation to explain how natural selection leads to adaptations within populations.

LS.Bio.9.4

Extinction

The History of Life on Earth
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Diversity and Extinction during the Paleogene Epoch
ExpandFirst, familiarize yourself with the extinction reading supplement for the background on what ...

Diversity and Extinction during the Paleogene Epoch
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Construct explanations to illustrate how varying environmental conditions may result in: changes in the number of individuals of a species, the emergence of new species over time, or the extinction of other species.

LS.Bio.10.1

Multi-species Conserved Sequences

Next-generation sequencing technologies have created large genomic databases of a variety of animals and plants. Ever since the human genome project was ...

Taxonomy

Taxonomy is the science of defining and naming groups of biological organisms based on shared characteristics. It uses a hierarchy of increasingly ...

Phylogeny

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Use models (including dichotomous keys, scientific nomenclature, cladograms, phylogenetic trees) to identify organisms and exemplify relationships.

Understand natural selection as a mechanism for biological evolution.

Chromosome Rearrangements and Synteny

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