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18 Dec 2019

A young man claiming to be the son she gave up for adoption 20years ago has approached a friend of yours. Your friend hasprovided a DNA sample to a lab for DNA analysis. Your friend doesnot understand this test and has asked you, her genetic expert, toexplain how this test can prove she is or isn

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Related questions

read the article. and video

https://www.youtube.com/watch?v=MW3ugmGt-9s

By referencing the textbook reading and the video; audio, answer the following questions:

1) Define karyotype.

2) Define Down Syndrome.

3) Describe the challenges addressed in the Perfect video. Compare and contrast to the Herzenberg family.

Only Human is a new podcast from WNYC Studios. Hosted by Mary Harris, Only Human tells stories we all can relate to. Because every body has a story. Subscribe to Only Human on iTunes or wherever you like to get your podcasts.

When Lee Herzenberg remembers the day her son Michael was born, she laughs and calls it a "cool birth." Her obstetrician was a friend, and she describes it almost like a party — "a little bit painful, but that you forget very quickly." Lee even got a kick out of the fact that a resident learned to do an episiotomy on her.

It was November 1961, and she was at the newly christened Palo Alto-Stanford Hospital Center; her husband, Len, was a biology professor on campus. Like most fathers at the time, he didn't attend the birth, which meant he wasn't there when Michael started turning blue.

The nurses whisked the newborn off to the nursery without telling Lee anything was wrong.

It was then that a doctor noticed the characteristic features of Down syndrome: floppy muscles, eyes that slanted upward. They got Michael breathing again, but doctors thought his prognosis was grim. They gave Michael just a few months to live. A daisy chain of physicians was called, and Lee says it was a pediatrics professor who told her husband what had happened. Then Len was dispatched to tell Lee.

She remembers the moment with uncharacteristic emotion. "We hugged each other, and it was a terrible conversation to realize that you'd lost the baby, but the baby was lost," Lee says now. "We knew immediately what we'd do. We had already made the decision that it was not a good thing to take the baby home, and so we didn't."

In the 1960s — an era before neurodiversity movements and early intervention programs — many people still called people with Down syndrome "mongoloids." Playwright Arthur Miller institutionalized his son, Daniel, in 1966. A few years later, an article in The Atlantic Monthly argued that "a Down's is not a person."

Lee and Len Herzenberg had seen friends struggle with the birth of a child with Down syndrome and had even gone with a colleague to an institution, where he dropped off his own infant daughter.

So, they decided Michael would never come home.

But Michael wasn't absolutely lost to them. Michael's birth sparked their search for a blood test that has revolutionized prenatal care in this country.

I made the mistake of telling one scientist I was reporting about "Len Herzenberg's lab." He corrected me instantly: "Len and Lee's lab." Because Lee Herzenberg was "leaning in" decades before Sheryl Sandberg coined the phrase. At 81, Lee, a professor of genetics, is still running the lab she and her husband founded more than 50 years ago. Len died in 2013.

The lab is a quirky place, even by Stanford standards. Lee rarely sits on chairs, preferring cushions on the floor. She's often accompanied by her bichon frise, Gigi. Researchers can often be found working in this basement office well into the night.

But Lee Herzenberg isn't just quirky. She is one of the few professors at Stanford — possibly the only one — never to have officially graduated from college. Instead, she trained by her husband's side, auditing courses while he got his Ph.D. at Caltech (women weren't allowed to attend at the time) and working at his labs at the Pasteur Institute in Paris and the National Institutes of Health.

And the science that's been done here has changed the course of medicine.

The Herzenbergs are best known as the creators of the modern-day fluorescence-activated flow cytometer, or FACS. It was a machine born out of frustration: Len couldn't stand squinting down a microscope looking at cells.

Before the FACS, a biologist peering at slides could feel like he was playing a really intense round of "Where's Waldo," staring at crowds of all kinds of cells, trying to pinpoint the exact ones he was looking for. Not only was it annoying — Len Herzenberg worried it wasn't particularly scientific. He wanted a way to find and describe cells that didn't rely on his worn-out eyes.

The FACS allows you to pour cells in, program the machine to find whatever it is you're looking for, and then it will spit out a little tube of just those cells alone. And the FACS gives you all kinds of information, too: how big the cells are and how much DNA they have inside.

The FACS was used to diagnose AIDS because the technology can quickly and easily sort out T cells. The FACS was used to find the first stem cells. When Len Herzenberg died, one colleague told The New York Times that "without Len, tens of thousands of people now alive would not be."

But in the 1970s, the Herzenbergs were still proving the value of this machine. That's when they started thinking about using it to create a blood test for Down syndrome.

Len had seen research from Finland claiming it was possible to see a fetus's cells in a mother's blood. It was hard to believe. But he figured that FACS, with its nearly magical sorting capabilities, could figure it out. So he took on a medical student named Diana Bianchi as a research associate and made sorting out these cells her project.

If they could isolate these cells, he could learn a lot about the developing fetus, including whether the fetus had chromosomal abnormalities.

"They had a very personal reason for doing this, because of their son Michael," Bianchi says now. "They wanted to have a test that could be offered to any pregnant woman — that would be noninvasive and would allow them to know if a child had Down syndrome. The first step, however, was to show that you could pull out fetal cells."

Scientists now estimate that for every 200 billion cells in a mother's bloodstream, about 10 of those are fetal cells. Bianchi was one of the first people to see them.

The New York Times quoted Len saying the work was a "first step" toward a blood test for Down syndrome for all pregnant women. But it would take 30 years for a practical test to become a reality.

As it turned out, Len's FACS wasn't the right tool for prenatal diagnosis. There weren't very many fetal cells to be sorted, and if a pregnant woman already had children, scientists couldn't be sure if the cells in her blood came from the current fetus or one of her older kids.

But in 2008, Len helped ensure the right tool was found.

A researcher named Stephen Quake had discovered a way to sequence chunks of fetal DNA floating in expectant mothers' blood. As a member of the National Academy of Sciences, Len made sure the paper was published in the academy's journal. Another researcher, Dennis Lo, confirmed Quake's findings. Three years later, the tests were on the market.

Now, at just 10 weeks into a pregnancy, a whole range of things can be revealed with this test. Not just Down syndrome, but a host of other chromosomal abnormalities as well as the sex of the child to be.

Until this test, doctors had to rely on amniocentesis, an invasive procedure that involves inserting a needle in the womb to sample amniotic fluid, or biopsying the placenta, to tell them with any reliability whether a fetus had a chromosomal abnormality. These tests aren't just uncomfortable; they come with a risk of miscarriage. By some estimates, in the past five years the number of these procedures performed in this country has plummeted by more than 50 percent.

To some parents, this knowledge can be alarming. Advocates in Ohio are trying to pass a law preventing abortions if Down syndrome is the reason (North Dakota and Indianahave already passed similar laws).

Lee Herzenberg is honest about what she would have done if she'd known early on in her pregnancy that Michael had Down syndrome.

"I'd say if I had the choice of not pushing Michael into this life — if I at that time would know I was carrying a Down syndrome child — I would have aborted the child," she says. "I see no reason Michael has to live the life he leads. The fact that we've made it very happy for him or that he's made it very happy for us — all of that is adapting to a situation, but I don't think it's fair or proper."

But Lee is alarmed that these tests are now being used to determine the sex of unborn babies. She worries about parents choosing to abort girls.

Diana Bianchi, that medical student from the Herzenberg lab, is now a professor at Tufts, where she founded the Mother Infant Research Institute. She's still working in prenatal testing. In fact, perfecting these tests has become her life's work.

But her focus has shifted. Now that she can detect Down syndrome so early, she wants to treat it early, too — in the womb. Because finding this chromosomal abnormality at 10 weeks means there's a window of opportunity: The brain changes associated with Down syndrome don't occur until a month or so later. Theoretically, you could treat a fetus before some brain changes occur at all.

Bianchi's work is still early. She's experimenting with mice, giving them existing drugs in utero to see if she can forestall brain damage.

There's an often-quoted statistic, that 90 percent of parents who find out that their fetus has Down syndrome will abort. But that statistic is from a study done in the United Kingdom. In the U.S., far fewer women terminate.

"We have to unpack this connection between prenatal testing and abortion," she says. "We have good data to suggest that approximately 40 plus percent of women who know their fetus has Down syndrome continue their pregnancy. There are many women who speak very highly of the fact that this allows them to prepare."

The Down syndrome baby who kicked off the search for this blood test is now a 54-year-old man. He lives in a squat house in Redwood City, Calif., just a 30-minute drive from his birth mother's home.

For years, Michael lived with a local woman named Barbara Jennings, who raised a number of children with developmental challenges. The Herzenbergs' pediatrician helped them find her when Michael was a newborn. The Herzenbergs would visit Michael every month or so, but they never felt they should bring him home. When Barbara died, Michael moved to this group home.

It's hard to know how much Michael understands when I speak to him, though he has learned to read and use a cellphone. And he's stubborn. A lot like his mother, actually. "Michael has the hardest head in the whole world," says Janet Thomas, the caretaker who runs this house. "He does whatever he wants to do. He does not care whatever you say. He's going to do whatever it is he wants to do — that's Michael."

I asked Lee if she ever regretted not raising Michael, and she said no. "It was a decision that was selfish, if you like, because we had things we wanted to do. In retrospect, a lot of things would never have gotten done. There would be no FACS had we decided to do this. Because it would have been a very intensive kind of upbringing."

As for Michael, he clearly loves his mother, no matter what she decided. In Michael's room, there are photos on almost every surface, with snapshots of his biological and adopted families. In the corner is a huge poster of his father, celebrating when he won the Kyoto Prize for his contributions to biotechnology. And deep in one album, there's a picture of Len and Lee together. The caption reads: "Michael's Other Mom + Dad."

On the Edge Selling Personalized Genetics

Several companies on the Internet sell genetic tests directly to consumers including 23andMe, Navigenics, decode Genetics, DNA Tribes, Genelex, ScientificMatch, Consumer Genetics, Salugen, DNAprint Genomics, Genova Diagnostics, Suracell, and many more. The companies ask customers to collect a sample of their genes with a cheek swab and send it to them for testing. Most test by putting the customer’s gene sample on a small flat “DNA microarray chip” that already contains pieces of DNA matching known genes (or gene mutations). If one of the customer’s genes matches one of the pieces of DNA on the chip, it binds to the DNA fragment which creates a tiny fluorescent glow showing that the gene indicated by the DNA fragment is in the sample. A computer then analyzes the pattern of glowing spots on the chip and prints out a list of the genes (or gene mutations) in the customer’s sample. Scientists have discovered a few genes that are associated with specific diseases or personal characteristics. Studies found, for example, genes that are linked to cystic fibrosis, Tay Sachs disease, and Lou Gehrig’s disease, genes that increase the risk of certain breast, colon, and thyroid cancers, and genes associated with sensation seeking, eye color, obesity, and lactose intolerance. They also found that some genes are more often found in people whose ancestors came from certain regions of the world. The companies say that based on these studies and their own gene tests, they can give customers valuable personalized information (for a price, of course). One company, Sciona, (no longer operating) said on its website: “Sciona is a leader in nutrigenomics, the science of personalizing your nutrition and lifestyle choices to match your genes”; Sciona gave customers “a personalized preventative dietary regime” that was supposed to prevent the diseases their genes put them at risk for. Another site promises: “Based upon the . . . [genetic] analysis, Suracell recommends to each client a personalized regimen of nutraceuticals [vitamin supplements].” Another states: “DNA Tribes . . . uses genetic material . . . to measure your genetic connections to individual ethnic groups and major world regions.” Another company claims to do it all: “With a simple saliva sample we’ll help you gain insight into your traits, from baldness to muscle performance. Discover risk factors for 95 diseases. Know your predicted response to drugs, from blood thinners to coffee. And uncover your ancestral origins.” Critics claim, however, that with a few exceptions, most studies have shown only weak connections between genes and specific traits, disease risks, drug responses, nutritional or vitamin needs, or ancestral origins. Many studies that link specific genes to a disease are only preliminary and the full picture has not yet been worked out. Moreover, critics say, it is wrong to tell customers their genes put them at risk of a deadly disease without proper counseling, especially when the scientific studies are weak and many other environmental, demographic, and lifestyle factors determine the actual onset of a disease. Ordinary consumers, they conclude, are being sold a product that they do not have the expertise to interpret. But defenders of the tests say consumers have a right to know what genes they carry and what science has learned about those genes. The companies charge from $140 to test for two or three genes, up to $999 to test for a full suite of genes. Evaluate the ethics of selling gene tests directly to consumers like these companies are doing. What would each of the three theories of a business’s duties to consumers say about what the companies are doing? Under what conditions do you think selling the tests would be ethically legitimate? Check out the video of GAO interviews of gene-test company salespeople at http://www.gao.gov/products/gao-10-847t .

Based on this issue evaluate the ethics of selling gene tests directly to consumers. Watch the video showing GAO interviews of the gene-test company salespeople and evaluate the ethics of the selling practices shown on the video. Answer the following questions:

1. What would the three theories of business's duties to consumers say about what the companies are doing?

2. Is it ever ethical for direct-to-consumer selling of these tests?

3. Should the government-on its own discretion-be able to use the DNA data in the databases to solve crimes and catch criminals?

http://www.gao.gov/products/GAO-10-847T

1.1 Maria is a genetic counselor and has a son who looks very much like her. Total strangers often say “He is your little clone—he looks just like you!” She’s tempted to retort, “No he’s not! You obviously don’t know anything about genetics!” but instead just says “Thank you.”

a. Based on what you know about genetics explain why Maria’s son could not be her clone.

b. Would it be legal to for Maria to make a clone of herself? Should it be? Explain your answer in 1-2 sentences.

1.2 When I was an undergraduate, a friend of mine who knew I was working on genetics offered to pay me a tidy sum to clone his dog Mitzi, who he loved dearly, so that he would never have to be without her. Although I could have used the money, I declined.

a. If I had cloned Mitzi, would Mitzi’s clone have been identical to Mitzi in appearance and behavior?

b. If she would not have been identical, explain why not in terms of genetics and gene expression.

1.3 (2 pts) List an example of a clone that is found in nature (rather than made in agricultural practice or the lab) in each of the following categories and escribe the characteristic(s) that qualify it to be considered a clone, in 1-2 sentences.

a. Single-celled organism

b. Plant

c. Animal

1.4 Plants have been genetically modified for many different reasons, which can be loosely grouped into two categories:

To increase yield. Examples include pesticide resistance, longer shelf-life modification and drought resistance.

To directly improve human health. Examples include: increasing the nutritional value of crops, removing allergenic substances, and using crops to produce vaccines.

Find one example of a crop in each category, then answer the following questions for each. Do not use examples we will discuss in class, which are BT, Round-up ready crops and Golden Rice, or other crops modified to make beta carotene.

a.GMO plants to increase yield (3 pts)

i.Name the GMO (e.g corn) and the gene or genes that were added or changed.

ii.What benefit(s) does the gene/s confer to the crop?

iii.Is this product in commercial use today?

iv.What are the regulations on the use of this product? Does it need to be labeled? Do farmers have to have a special permit to grow it?

v.What is one concern regarding the use of this crop?

b.GMO plants to benefit human health (3 pts)

i.Name the GMO (e.g corn) and the gene or genes that were added or changed.

ii.What benefit(s) does the gene/s confer to humans?

iii.Is this product in commercial use today?

iv.What are the regulations on the use of this product? Does it need to be labeled? Do farmers have to have a special permit to grow it?

v. What is one concern regarding the use of this crop?

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