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Posts tagged "genetics"
42violethill: “Molecular structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid” was an article published by James D. Watson and Francis Crick in the scientific journal Nature in its 171st volume on pages 737–738 (dated April 25, 1953). It was the first publication which described Rosalind Franklin’s discovery of the double helix structure of DNA. This discovery had a major impact onbiology, particularly in the field of genetics. This article is often termed a “pearl” of science because it is brief and contains the answer to a fundamental mystery about living organisms. This mystery was the question of how it was possible thatgenetic instructions were held inside organisms and how they were passed from generation to generation. The article presents a simple and elegant solution, which surprised many biologists at the time who believed that DNA transmission was going to be more difficult to detail and understand. Image Credit: DNA Replication Animation Happy Birthday DNA!!!!

42violethill:

“Molecular structure of Nucleic Acids: A Structure for Deoxyribose Nucleic Acid” was an article published by James D. Watson and Francis Crick in the scientific journal Nature in its 171st volume on pages 737–738 (dated April 25, 1953). It was the first publication which described Rosalind Franklin’s discovery of the double helix structure of DNA. This discovery had a major impact onbiology, particularly in the field of genetics.

This article is often termed a “pearl” of science because it is brief and contains the answer to a fundamental mystery about living organisms. This mystery was the question of how it was possible thatgenetic instructions were held inside organisms and how they were passed from generation to generation. The article presents a simple and elegant solution, which surprised many biologists at the time who believed that DNA transmission was going to be more difficult to detail and understand.

Image Credit: DNA Replication Animation

Happy Birthday DNA!!!!

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Squid’s Daily Rhythms Are Controlled by Glowing Symbiotic Bacteria At nightfall, the Hawaiian bobtail squid digs itself out of the sand and rises into the ocean water like a spaceship taking off. It switches on its cloaking device: glowing bacteria inside its body light up, disguising the squid’s silhouette against the moonlight for any predators swimming below. As sleek a vehicle as it appears, though, the bobtail may not totally outrank its microscopic crewmembers. The bacteria seem to power a clock inside the squid’s body that can’t function without them.Hiding during the day and hunting at night in shallow Pacific waters, Euprymna scolopes clearly has a working circadian clock. Researchers had noticed, though, that the squid’s light organ—the specialized pocket inside its body that houses its bacterial helpers—seemed to have a rhythm of its own. The Vibrio fischeri bacteria give off fluctuating amounts of light throughout the day, for one thing. And the bacteria have their own daily rhythm of gene expression (when various genes are turned on or off), explains Margaret McFall-Ngai, a microbiologist at the University of Wisconsin, Madison.McFall-Ngai and her coauthors looked for genes linked to circadian rhythms within the squid. They found two types of “cry” genes, which are known to control internal clocks throughout the animal and plant kingdoms. One gene had a daily cycle of activity in the squid’s head—which is what you’d expect, since animals’ main circadian clocks are in our brains. Other clocks can be elsewhere in the body, though, and this is what researchers found with the second cry gene. It was cycling only within the light organ.Baby squid, which hadn’t yet collected bacterial friends in their light organs, didn’t show the same cycling. So it seemed that the bacteria themselves were driving the daily rhythms in the light organ. When the researchers let squid fill their light organs with defective, non-glowing bacteria, the cry gene still didn’t cycle properly. This suggested that the glow of the bacteria was the crucial ingredient. Full Article

Squid’s Daily Rhythms Are Controlled by Glowing Symbiotic Bacteria

At nightfall, the Hawaiian bobtail squid digs itself out of the sand and rises into the ocean water like a spaceship taking off. It switches on its cloaking device: glowing bacteria inside its body light up, disguising the squid’s silhouette against the moonlight for any predators swimming below. As sleek a vehicle as it appears, though, the bobtail may not totally outrank its microscopic crewmembers. The bacteria seem to power a clock inside the squid’s body that can’t function without them.

Hiding during the day and hunting at night in shallow Pacific waters, Euprymna scolopes clearly has a working circadian clock. Researchers had noticed, though, that the squid’s light organ—the specialized pocket inside its body that houses its bacterial helpers—seemed to have a rhythm of its own. The Vibrio fischeri bacteria give off fluctuating amounts of light throughout the day, for one thing. And the bacteria have their own daily rhythm of gene expression (when various genes are turned on or off), explains Margaret McFall-Ngai, a microbiologist at the University of Wisconsin, Madison.

McFall-Ngai and her coauthors looked for genes linked to circadian rhythms within the squid. They found two types of “cry” genes, which are known to control internal clocks throughout the animal and plant kingdoms. One gene had a daily cycle of activity in the squid’s head—which is what you’d expect, since animals’ main circadian clocks are in our brains. Other clocks can be elsewhere in the body, though, and this is what researchers found with the second cry gene. It was cycling only within the light organ.

Baby squid, which hadn’t yet collected bacterial friends in their light organs, didn’t show the same cycling. So it seemed that the bacteria themselves were driving the daily rhythms in the light organ. When the researchers let squid fill their light organs with defective, non-glowing bacteria, the cry gene still didn’t cycle properly. This suggested that the glow of the bacteria was the crucial ingredient.

Full Article

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In ants and bees, there are no sex chromosomes. Instead, sex is determined by whether or not an egg was fertilized. If the egg isn’t fertilized, the offspring is male. If the egg is fertilized, it’s female. So male ants have no fathers, and they have half as many chromosomes as females. Poor little things.

Beatrice the Biologist: Clarification, Sex Determination, and Cheesecake

(via chopdawg)

(via chopdawg)

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skeptv:

How Mendel’s pea plants helped us understand genetics - Hortensia Jiménez Díaz

View full lesson: http://ed.ted.com/lessons/how-mendel-s-pea-plants-helped-us-understand-genetics-hortensia-jimenez-diaz

Each father and mother pass down traits to their children, who inherit combinations of their dominant or recessive alleles. But how do we know so much about genetics today? Hortensia Jiménez Díaz explains how studying pea plants revealed why you may have blue eyes.

Lesson by Hortensia Jiménez Díaz, animation by Cinematic Sweden.

by TED Education.

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genannetics: The Immortal Life of Henrietta Lacks, the Sequel  Rebecca Skloot, author of the extremely popular non-fiction novel “The Immortal Life of Henrietta Lacks,” once again raises important moral and ethical dilemmas behind the ubiquitous HeLa cells, this time surrounding the recent publication of the HeLa cell genome. LAST week, scientists sequenced the genome of cells taken without consent from a woman named Henrietta Lacks. She was a black tobacco farmer and mother of five, and though she died in 1951, her cells, code-named HeLa, live on. They were used to help develop our most important vaccines and cancer medications, in vitro fertilization, gene mapping, cloning. Now they may finally help create laws to protect her family’s privacy — and yours. Now, HeLa cells cells have been back in the news, when researchers published the HeLa cell genome, seemingly without consent from the Lacks family.  This raises new questions surrounding genetic information and privacy.  How much can we learn from a raw human genome?  What are the major ethical issues behind using genetic material in research, and what does it mean to give consent? I highly recommend Rebecca Skloot’s book, as well as this new article.  Issues behind the dissemination of genetic information, and what sort of laws/oversight need to be used to protect individual privacy are quickly becoming increasingly relevant to the research community and the general public.

genannetics:

The Immortal Life of Henrietta Lacks, the Sequel

 Rebecca Skloot, author of the extremely popular non-fiction novel “The Immortal Life of Henrietta Lacks,” once again raises important moral and ethical dilemmas behind the ubiquitous HeLa cells, this time surrounding the recent publication of the HeLa cell genome.

LAST week, scientists sequenced the genome of cells taken without consent from a woman named Henrietta Lacks. She was a black tobacco farmer and mother of five, and though she died in 1951, her cells, code-named HeLa, live on. They were used to help develop our most important vaccines and cancer medications, in vitro fertilization, gene mapping, cloning. Now they may finally help create laws to protect her family’s privacy — and yours.

Now, HeLa cells cells have been back in the news, when researchers published the HeLa cell genome, seemingly without consent from the Lacks family.  This raises new questions surrounding genetic information and privacy.  How much can we learn from a raw human genome?  What are the major ethical issues behind using genetic material in research, and what does it mean to give consent?

I highly recommend Rebecca Skloot’s book, as well as this new article.  Issues behind the dissemination of genetic information, and what sort of laws/oversight need to be used to protect individual privacy are quickly becoming increasingly relevant to the research community and the general public.

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The Father of All Men Is 340,000 Years Old A change in the way we understand the root of the tree where Y chromosome originated from has left geneticists amazed Albert Perry carried a secret in his DNA: a Y chromosome so distinctive that it reveals new information about the origin of our species. It shows that the last common male ancestor down the paternal line of our species is over twice as old as we thought. One possible explanation is that hundreds of thousands of years ago, modern and archaic humans in central Africa interbred, adding to known examples of interbreeding – with Neanderthals in the Middle East, and with the enigmatic Denisovans somewhere in southeast Asia. Perry, recently deceased, was an African-American who lived in South Carolina. A few years ago, one of his female relatives submitted a sample of his DNA to a company called Family Tree DNA for genealogical analysis. Geneticists can use such samples to work out how we are related to one another. Hundreds of thousands of people have now had their DNA tested. The data from these tests had shown that all men gained their Y chromosome from a common male ancestor. This genetic “Adam” lived between 60,000 and 140,000 years ago. All men except Perry, that is. When Family Tree DNA’s technicians tried to place Perry on the Y-chromosome family tree, they just couldn’t. His Y chromosome was like no other so far analysed. — “The Y-chromosome tree is much older than we thought,” says Chris Tyler-Smith at the Wellcome Trust Sanger Institute in Hinxton, UK, who was not involved in the study. He says further work will be needed to confirm exactly how much older. “It’s a cool discovery,” says Jon Wilkins of the Ronin Institute in Montclair, New Jersey. “We geneticists have been looking at Y chromosomes about as long as we’ve been looking at anything. Changing where the root of the Y-chromosome tree is at this point is extremely surprising.” (via NewScientist)

The Father of All Men Is 340,000 Years Old

A change in the way we understand the root of the tree where Y chromosome originated from has left geneticists amazed

Albert Perry carried a secret in his DNA: a Y chromosome so distinctive that it reveals new information about the origin of our species. It shows that the last common male ancestor down the paternal line of our species is over twice as old as we thought.

One possible explanation is that hundreds of thousands of years ago, modern and archaic humans in central Africa interbred, adding to known examples of interbreeding – with Neanderthals in the Middle East, and with the enigmatic Denisovans somewhere in southeast Asia.

Perry, recently deceased, was an African-American who lived in South Carolina. A few years ago, one of his female relatives submitted a sample of his DNA to a company called Family Tree DNA for genealogical analysis.

Geneticists can use such samples to work out how we are related to one another. Hundreds of thousands of people have now had their DNA tested. The data from these tests had shown that all men gained their Y chromosome from a common male ancestor. This genetic “Adam” lived between 60,000 and 140,000 years ago.

All men except Perry, that is. When Family Tree DNA’s technicians tried to place Perry on the Y-chromosome family tree, they just couldn’t. His Y chromosome was like no other so far analysed.

—

“The Y-chromosome tree is much older than we thought,” says Chris Tyler-Smith at the Wellcome Trust Sanger Institute in Hinxton, UK, who was not involved in the study. He says further work will be needed to confirm exactly how much older.

“It’s a cool discovery,” says Jon Wilkins of the Ronin Institute in Montclair, New Jersey. “We geneticists have been looking at Y chromosomes about as long as we’ve been looking at anything. Changing where the root of the Y-chromosome tree is at this point is extremely surprising.”

(via NewScientist)

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Girl Who Doesn’t Grow Baffles Doctors Little Brooke Greenberg has shining eyes that twinkle when her mother takes her clothes’ shopping, pushing her stroller through the infant wear department of their local stores, where Brooke gets her clothes. But Brooke is 20 years old this year, and she hasn’t grown an inch since she was 4 or 5 years old. Her story is a medical mystery that has baffled some of the finest doctors in the world, according to the Daily Mail. “Many of the best-known names in medicine, in their experience … had not seen anyone who matched up to Brooke,” pediatrician Lawrence Pakula of Johns Hopkins School of Medicine in Baltimore told ABC News. “She is always a surprise.” Because no doctor has ever been able to provide a formal diagnosis for Brooke’s condition, her condition has been labeled “Syndrome X.” Weighing just 16 (7 kilograms), she is estimated to have the mental capacity of a toddler. Brooke has “no apparent abnormalities in her endocrine system, no gross chromosomal abnormalities, or any of the other disruptions known to occur in humans that can cause developmental issues,” said Dr. Eric Schadt, director of the Icahn Institute for Genomics and Multiscale Biology at Mount Sinai Medical Center in New York, reports the Daily Mail. Her Baltimore-area family treats Brooke like any other child, insisting she does not need to be cured: “If somebody knocked on the door right now and said, ‘It’s a guaranteed pill. Give this to Brooke and she’ll be fixed,’ well, first I would say to him, ‘She’s not broken,’” her father Howard told Katie Couric on her daily live talk show. Nonetheless, the baffling nature of Brooke’s condition has led some researchers to believe her unique genetic code could provide insights into the aging process, according to the Daily Mail. Schadt and other geneticists are now sequencing Brooke’s genome in the hopes that it may someday lead to new treatments for age-related disorders like Parkinson’s disease.

Girl Who Doesn’t Grow Baffles Doctors

Little Brooke Greenberg has shining eyes that twinkle when her mother takes her clothes’ shopping, pushing her stroller through the infant wear department of their local stores, where Brooke gets her clothes.

But Brooke is 20 years old this year, and she hasn’t grown an inch since she was 4 or 5 years old. Her story is a medical mystery that has baffled some of the finest doctors in the world, according to the Daily Mail.

“Many of the best-known names in medicine, in their experience … had not seen anyone who matched up to Brooke,” pediatrician Lawrence Pakula of Johns Hopkins School of Medicine in Baltimore told ABC News. “She is always a surprise.”

Because no doctor has ever been able to provide a formal diagnosis for Brooke’s condition, her condition has been labeled “Syndrome X.” Weighing just 16 (7 kilograms), she is estimated to have the mental capacity of a toddler.

Brooke has “no apparent abnormalities in her endocrine system, no gross chromosomal abnormalities, or any of the other disruptions known to occur in humans that can cause developmental issues,” said Dr. Eric Schadt, director of the Icahn Institute for Genomics and Multiscale Biology at Mount Sinai Medical Center in New York, reports the Daily Mail.

Her Baltimore-area family treats Brooke like any other child, insisting she does not need to be cured: “If somebody knocked on the door right now and said, ‘It’s a guaranteed pill. Give this to Brooke and she’ll be fixed,’ well, first I would say to him, ‘She’s not broken,’” her father Howard told Katie Couric on her daily live talk show.

Nonetheless, the baffling nature of Brooke’s condition has led some researchers to believe her unique genetic code could provide insights into the aging process, according to the Daily Mail. Schadt and other geneticists are now sequencing Brooke’s genome in the hopes that it may someday lead to new treatments for age-related disorders like Parkinson’s disease.

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wespeakfortheearth:

How do coral reef conservationists balance the environmental needs of the reefs with locals who need the reefs to survive? Joshua Drew draws on the islands of Fiji and their exemplary system of protection, called “connectivity”, which also keep the needs of fishermen in mind.

Lesson by Joshua Drew, animation by Veronica Wallenberg

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science-junkie: Turning vast amounts of genomic data into meaningful information about the cell is the great challenge of bioinformatics, with major implications for human biology and medicine. Researchers at the University of California, San Diego School of Medicine and colleagues have proposed a new method that creates a computational model of the cell from large networks of gene and protein interactions, discovering how genes and proteins connect to form higher-level cellular machinery. The findings are published in the December 16 advance online publication of Nature Biotechnology. “Our method creates ontology, or a specification of all the major players in the cell and the relationships between them,” said first author Janusz Dutkowski, PhD, postdoctoral researcher in the UC San Diego Department of Medicine. It uses knowledge about how genes and proteins interact with each other and automatically organizes this information to form a comprehensive catalog of gene functions, cellular components, and processes. “What’s new about our ontology is that it is created automatically from large datasets. In this way, we see not only what is already known, but also potentially new biological components and processes – the bases for new hypotheses,” said Dutkowski. (via Toward a new model of the cell)

science-junkie:

Turning vast amounts of genomic data into meaningful information about the cell is the great challenge of bioinformatics, with major implications for human biology and medicine. Researchers at the University of California, San Diego School of Medicine and colleagues have proposed a new method that creates a computational model of the cell from large networks of gene and protein interactions, discovering how genes and proteins connect to form higher-level cellular machinery.

The findings are published in the December 16 advance online publication of Nature Biotechnology.

“Our method creates ontology, or a specification of all the major players in the cell and the relationships between them,” said first author Janusz Dutkowski, PhD, postdoctoral researcher in the UC San Diego Department of Medicine. It uses knowledge about how genes and proteins interact with each other and automatically organizes this information to form a comprehensive catalog of gene functions, cellular components, and processes.

“What’s new about our ontology is that it is created automatically from large datasets. In this way, we see not only what is already known, but also potentially new biological components and processes – the bases for new hypotheses,” said Dutkowski.

(via Toward a new model of the cell)

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genannetics:

DNA imaged with electron microscope for the first time

It’s the most famous corkscrew in history. Now an electron microscope has captured the famous Watson-Crick double helix in all its glory.

This is an image of six or seven molecules of DNA wrapped around a core, taken with TEM (transmission electron microscopy).  The team of scientists that published these images in Nanostructures this month used the hydrophobic nature of DNA molecules to suspend and stretch them between silicon pillars.

May I just say, gosh, helix, your beautiful!

(via ikenbot)

Photoset
sciencenote: TALENs: a widely applicable technology for targeted genome editing J. Keith Joung & Jeffry D. Sander Abstract Engineered nucleases enable the targeted alteration of nearly any gene in a wide range of cell types and organisms. The newly-developed transcription activator-like effector nucleases (TALENs) comprise a nonspecific DNA-cleaving nuclease fused to a DNA-binding domain that can be easily engineered so that TALENs can target essentially any sequence. The capability to quickly and efficiently alter genes using TALENs promises to have profound impacts on biological research and to yield potential therapeutic strategies for genetic diseases.

sciencenote:

TALENs: a widely applicable technology for targeted genome editing

J. Keith Joung & Jeffry D. Sander

Engineered nucleases enable the targeted alteration of nearly any gene in a wide range of cell types and organisms. The newly-developed transcription activator-like effector nucleases (TALENs) comprise a nonspecific DNA-cleaving nuclease fused to a DNA-binding domain that can be easily engineered so that TALENs can target essentially any sequence. The capability to quickly and efficiently alter genes using TALENs promises to have profound impacts on biological research and to yield potential therapeutic strategies for genetic diseases.

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sciencenote: Skin Cells Reveal DNA’s Genetic Mosaic “We found that humans are made up of a mosaic of cells with different genomes,” said lead author Dr. Flora Vaccarino, the Harris Professor of Child Psychiatry at the Yale Child Study Center. “We saw that 30 percent of skin cells harbor copy number variations (CNV), which are segments of DNA that are deleted or duplicated. Previously it was assumed that these variations only occurred in cases of disease, such as cancer. The mosaic that we’ve seen in the skin could also be found in the blood, in the brain, and in other parts of the human body.” … “In the skin, this mosaicism is extensive and at least 30 percent of skin cells harbor different deletion or duplication of DNA, each found in a small percentage of cells,” said Vaccarino. “The observation of somatic mosaicism has far-reaching consequences for genetic analyses, which currently use only blood samples. When we look at the blood DNA, it’s not exactly reflecting the DNA of other tissues such as the brain. There could be mutations that we’re missing.” “These findings are shaping our future studies, and we’re doing more studies of the developing brains of animals and humans to see if this variation exists there as well,” Vaccarino added.

sciencenote:

Skin Cells Reveal DNA’s Genetic Mosaic

“We found that humans are made up of a mosaic of cells with different genomes,” said lead author Dr. Flora Vaccarino, the Harris Professor of Child Psychiatry at the Yale Child Study Center. “We saw that 30 percent of skin cells harbor copy number variations (CNV), which are segments of DNA that are deleted or duplicated. Previously it was assumed that these variations only occurred in cases of disease, such as cancer. The mosaic that we’ve seen in the skin could also be found in the blood, in the brain, and in other parts of the human body.”

…

“In the skin, this mosaicism is extensive and at least 30 percent of skin cells harbor different deletion or duplication of DNA, each found in a small percentage of cells,” said Vaccarino. “The observation of somatic mosaicism has far-reaching consequences for genetic analyses, which currently use only blood samples. When we look at the blood DNA, it’s not exactly reflecting the DNA of other tissues such as the brain. There could be mutations that we’re missing.”

“These findings are shaping our future studies, and we’re doing more studies of the developing brains of animals and humans to see if this variation exists there as well,” Vaccarino added.

(via ikenbot)

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sciencecenter: World’s First Liliger Born in Russia This news is a bit dated, but certainly worth checking out. If you saw Napoleon Dynamite, then you know that a liger is a hybrid cross between a male lion and a female tiger. Ligers are actually relatively common, and when the territories of lions and tigers historically overlapped, ligers were probably found. A liliger, however, takes the hybridization one step further - it’s the offspring of a hybrid female liger and a male lion. Pictured above is the world’s first liliger, Kiara, who was born in August in Russia’s Novosibirsk Zoo. What she lacks in genealogical cleanliness, she more than makes up for in cuteness.  If your appetite for the incredible isn’t whetted by the simple arrival of a liliger, then keep paying attention. Kiara’s mother, the liger, couldn’t produce enough milk to sustain her - possibly as a result of her hybrid genes. Therefore, Kiara is being raised by Dasha, an ordinary house cat. I wonder what the people against gay marriage would think about this double-hybrid interspecies adoptive single-mother family. I think maybe we just won’t tell them. Quick Links HuffPo article - with video! Liger - Wikipedia Liliger bred in zoo - Why Evolution Is True

sciencecenter:

World’s First Liliger Born in Russia

This news is a bit dated, but certainly worth checking out. If you saw Napoleon Dynamite, then you know that a liger is a hybrid cross between a male lion and a female tiger. Ligers are actually relatively common, and when the territories of lions and tigers historically overlapped, ligers were probably found. A liliger, however, takes the hybridization one step further - it’s the offspring of a hybrid female liger and a male lion. Pictured above is the world’s first liliger, Kiara, who was born in August in Russia’s Novosibirsk Zoo. What she lacks in genealogical cleanliness, she more than makes up for in cuteness. 

If your appetite for the incredible isn’t whetted by the simple arrival of a liliger, then keep paying attention. Kiara’s mother, the liger, couldn’t produce enough milk to sustain her - possibly as a result of her hybrid genes. Therefore, Kiara is being raised by Dasha, an ordinary house cat.

I wonder what the people against gay marriage would think about this double-hybrid interspecies adoptive single-mother family. I think maybe we just won’t tell them.

Quick Links

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mothernaturenetwork: Many low IQs are the result of bad gene luckScientists have discovered that many cases of low IQ or mental retardation result from random new mutations that arise spontaneously, not from faulty genes inherited from parents.

mothernaturenetwork:

Many low IQs are the result of bad gene luck
Scientists have discovered that many cases of low IQ or mental retardation result from random new mutations that arise spontaneously, not from faulty genes inherited from parents.

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sciencenote: Colourful Chromosomes Our cells each have 23 pairs of chromosomes - lengths of DNA where genes are arranged like books on a bookshelf waiting to be read. Mice usually have 20 pairs, but in this picture cancer has caused some dramatic rearrangements. Using a technique called spectral karyotyping, chromosomes are grouped in different colours (each chromosome is seen here as a coloured blob and as a black and white image). Instead of the ordered pairs we would expect, this tumour has developed three copies of chromosomes 1, 16 and 19, while chromosomes 12 (pink) and 15 (light green) have merged together. Merging or translocation of chromosomes happens in human cancers too. In cases of Burkitt’s lymphoma, genes from chromosomes 8 and 14 fuse together, driving cells to reproduce too quickly. Discovering which genes are affected by translocation has already influenced new, targeted cancer therapies. Written by John Ankers Chromosomes are not visible in the cell’s nucleus—not even under a microscope—when the cell is not dividing. However, the DNA that makes up chromosomes becomes more tightly packed during cell division and is then visible under a microscope. Most of what researchers know about chromosomes was learned by observing chromosomes during cell division.

sciencenote:

Colourful Chromosomes

Our cells each have 23 pairs of chromosomes - lengths of DNA where genes are arranged like books on a bookshelf waiting to be read. Mice usually have 20 pairs, but in this picture cancer has caused some dramatic rearrangements. Using a technique called spectral karyotyping, chromosomes are grouped in different colours (each chromosome is seen here as a coloured blob and as a black and white image). Instead of the ordered pairs we would expect, this tumour has developed three copies of chromosomes 1, 16 and 19, while chromosomes 12 (pink) and 15 (light green) have merged together. Merging or translocation of chromosomes happens in human cancers too. In cases of Burkitt’s lymphoma, genes from chromosomes 8 and 14 fuse together, driving cells to reproduce too quickly. Discovering which genes are affected by translocation has already influenced new, targeted cancer therapies.

Written by John Ankers

Chromosomes are not visible in the cell’s nucleus—not even under a microscope—when the cell is not dividing. However, the DNA that makes up chromosomes becomes more tightly packed during cell division and is then visible under a microscope. Most of what researchers know about chromosomes was learned by observing chromosomes during cell division.

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