How Can 1 Person Have 2 Different Sets of DNA?

Image by Elias Sch. from Pixabay

A human with two different sets of DNA is called a chimera, and it’s more common than you might think. Most chimeras don’t even know they have this strange phenomenon going on inside them.

You could be a chimera, and so could I.

As we go along, take note of the interesting tidbits you could twist into a plot to add conflict.

Without any help from the scientific community, the process of becoming a chimera occurs naturally. Numerous books and movies explore chimerism using a killer who’s had a bone marrow transplant or blood transfusion. But are these characters based in fact?

Let’s take a look and find out.

The tissue inside our bones is called bone marrow, and it’s responsible for making white blood cells, red blood cells, and platelets. When someone has a bone marrow transplant, doctors use chemotherapy or radiation to destroy all the recipient’s diseased bone marrow. The donor’s healthy marrow is then introduced and continues to produce blood cells with the donor’s DNA, thereby transforming the recipient into a chimera.

In some cases, all of the blood cells in a person who received a bone marrow transplant will match the DNA of their donor. But in other cases, the recipient may have a mix of both their own blood cells and donor cells. A blood transfusion will also temporarily give a person cells from someone else, but in a bone marrow transplant, the new blood cells are permanent, according to the Tech Museum of Innovation in San Jose, California.

What if we’ve never had a transplant?

Doesn’t matter. There are other ways to become a chimera.

Early on in pregnancy a mother can be carrying fraternal twins and one of the embryos might die in utero. The surviving embryo may absorb cells from the deceased twin. When the baby is born, s/he can have two sets of DNA. Since twin loss occurs in 21-30% of multiple-fetus pregnancies, think of how many chimeras could be walking around. Are the story wheels spinning yet?

It can also happen with a normal pregnancy.

In the 1990s, scientists discovered that a pregnant woman may retain some DNA from her baby, if fetal cells happen to migrate into her bloodstream and travel to different organs. The New York Times referred to this as a “pregnancy souvenir”— but it’s more scientifically known as “microchimerism.”

A 2015 study suggests this happens in almost ALL pregnancies (you read that right), at least temporarily. The researchers tested tissue samples from the kidneys, livers, spleens, lungs, hearts, and brains of 26 women who died while pregnant or within one month of giving birth. The study found fetal cells in all of the women’s tissues. The researchers were able to tell the fetus cells from the mothers by searching for Y chromosomes (only found in males). The deceased mothers were all carrying sons.

Writers: Don’t take the obvious road. Think victims instead of killers.

  • What if a human brain washed up on the beach?
  • What if the Medical Examiner wrongly assumed the victim was male due to the Y chromosomes?

This is one way to use research to our advantage.

  • What if the brain contained animal and human DNA?

Remember, we’re thinking victim, not killer, which puts a different spin on it.

According to Live Science, fetal cells may stay in a woman’s body for years. In a 2012 study, researchers analyzed the brains of 59 deceased women ages 32 to 101. A shocking 63 percent had traces of male DNA from fetal cells in their brains. The oldest woman died at 94 years old, suggesting that these cells can sometimes last a lifetime.

The blood-brain barrier is the body’s defense system to block many drugs and germs in the bloodstream from entering the brain, but doctors have found this barrier becomes more permeable during pregnancy, which may explain how these fetal cells migrated into the brains of their mothers.

  • What if a serial killer only targeted people with chimerism because s/he viewed them as freaks of nature?
  • How might the killer find potential victims?

If you said the medical field, you’re not thinking outside the box.

Interestingly enough, 26 of the 59 women had no signs of brain disorders while alive. The other 33 were diagnosed with Alzheimer’s disease. The researchers found that women with Alzheimer’s were less likely to have male DNA in their brains than women without the disease.

Previous work on microchimerism suggested fetal cells might protect against breast cancer and aid tissue repair in the mothers, but could increase the risk of colon cancer. Microchimerism can also incite various autoimmune diseases. Autoimmune diseases occur when a person’s body is mistakenly attacked by its own immune system.

Past research suggested Alzheimer’s is more common in women who had a high number of pregnancies than in childless women. One of the limitations of this research is that the number of brains studied was relatively small. Other researchers involved with microchimerism want to explore what effects a mother’s cells might have in her offspring’s development and health.

Imagine all the different scenarios? Parts of your writer brain must be on fire by now. No? Then check this out …  

Are you a chimera? 

You may never know. Unless you wind up in a similar situation to a woman named Karen Keegan. In 2002, her story became a report in the New England Journal of Medicine after doctors told her that she wasn’t the biological mother of her children.

Imagine? Think of all the ways this one conversation could implode an MC’s life.

  • Maybe the woman’s marriage broke up and the only reason her and her husband reunited was because she said she gave birth to his child while he was stationed overseas.

Turns out, the DNA in Karen Keegan’s bloodstream didn’t match the DNA in her ovaries. The doctors later determined she’d most likely absorbed a fraternal twin in utero.

How’s the ol’ writer brain feeling now?

 

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Can Creativity Pass Through Generations via DNA?

By SUE COLETTA

This video sent me down a rabbit hole of research.

As you can imagine, my writer brain lit up. Turns out, the research was even more fascinating than the video. A scientific study showed that a traumatic event could affect the DNA in sperm or eggs and alter the brains and behavior of subsequent generations. This breakthrough is an important discovery in the fight to treat phobias and anxiety.

Do you fear spiders, heights, or small spaces for no apparent reason? This may explain why.

Neuroscientists trained mice to fear a cherry blossom scent prior to copulation. While breeding these mice, the team at the Emory University School of Medicine looked at what was happening inside the sperm. Incredibly, the sperm showed a section of DNA, responsible for sensitivity to the cherry blossom scent, was indeed more active.

The mice’s offspring, and their offspring — the grand-mice, if you will — were all extremely sensitive to cherry blossom and avoided the scent at all costs, despite never experiencing a problem with it in their lives. They also found changes in brain structure.

In the smell-aversion study, scientists believe either some of the odor ended up in the bloodstream, which affected sperm production, or the brain sent a signal to the sperm to alter the DNA.

The report states, “Our findings provide a framework for addressing how environmental information may be inherited transgenerationally at behavioral, neuroanatomical and epigenetic levels.”

Enivronmental change can also critically affect the lifestyle, reproductive success, and lifespan of adult animals for generations. Exposure to high temperatures led to the expression of endogenously repressed copies of genes — sometimes referred to as “junk” DNA. The changes in chromatin occurred in the early embryo before the onset of transcription and were inherited through eggs and sperm. In mealworms, they traced the DNA changes through 14 generations.

Why mealworms? It’s quicker to test generation after generation on an animal with a short lifespan.

Another study showed that a mouse’s ability to remember can be affected by the presence of immune system factors in their mother’s milk. Chemokines — signaling proteins secreted by cells — carried in a mother’s milk caused changes in the brains of their offspring, affecting their memory later in life.

Memories are passed down through generations via genetic switches that allow offspring to inherit the experience of their ancestors. These switches, however, can be turned on and off, according to Science Daily. Scientists have long assumed that memories and learned experiences must be passed to future generations through personal interactions. However, this research shows that it’s possible for some information to be inherited biologically through chemical changes that occur in DNA.

Creativity counts as a learned behavior, but I also believe it goes deeper than that. Think about how deeply you feel about your writing. For most writers I know, when we’re “in the zone” our soul does the writing. One could argue we’re merely vessels who type. Have you ever read a passage that you don’t remember writing? Our ability to create burrows into the core of who we are, and thus, leaves an indelible mark. How, then, can we not pass that part of ourselves to future generations?

How many of you have creative folks in your family tree, be it writers, artists, musicians, singers, or other forms of creativity?

To test my theory, I asked the same question to my fellow TKZ members. Please note: this revelation occurred to me yesterday, so I’ve only included the members who saw the email in time. Hopefully, the others will add their responses in the comments.

For those I did catch on a Sunday, check out what they said …

Elaine Viets said, “My late cousin Kurt was a talented wood carver, and my grandfather was known as a great story teller in the local saloons.”

I love wood-carved pieces. The smell, the texture, the swirl to the grain. It’s not an easy creative outlet to master.

Jordan Dane comes from a long line of creative people. Here’s her answer: “My paternal grandfather was a writer for a Hispanic newspaper. My dad was an architect and artist (painter), my older brother went into architecture too, specializing in hospital design. My dad is a real renaissance guy. He could sculpt, paint, draw and he has a passion for cooking. My older brother Ed and I share a love for singing. I sang in competitive ensemble groups. He played in a popular area band and has sung in barbershop quartets. My mom was the original singer in our family. She has a great voice.”

Joe Hartlaub has two talented children. Here’s what he said, “Annalisa Hartlaub, my youngest daughter, is a photographer. My oldest son Joe is also a highly regarded bass guitar player locally.”

He’s being modest. When I checked out Annalisa’s photographs on Facebook and Instagram they blew me away. A photography project she created at 15 years old also went viral.

When I prodded further, Joe added, “My maternal grandfather played guitar, but we never knew it until we came across a picture of him taken at a large Italian social club gathering where he was strumming away. He was in his twenties at the time. As far as the source of Annalisa’s talent goes…her mother is a terrific photographer. The conclusion is that Annalisa gets the form of the art from her mother and her creativeness from me.”

Laura Benedict stunned me with her answer. “Someone doing genealogy linked my maternal grandfather’s family to Johann Sebastian Bach.”

Talk about a creative genius!

Laura added, “I remember a few very small watercolors that I believe my maternal grandmother painted. Trees and houses. But while we were close, we never talked about art. My aunt also did some drawing.”

John Gilstrap also came from a long line of creative people. Here’s his answer…

“My paternal extended family has always been fairly artistic.  My grandfather, I am told–he died long before I was born–had a beautiful singing voice, and for a period of time worked whatever the Midwest version of the Vaudeville circuit was.  My father, a career Naval aviator, wrote the Navy’s textbook, The Principles of Helicopter Flight, and had two patents on helicopter cargo handling operations.  He passed away in 2006.

My brother, four years older than I, plays a number of instruments, but his primary proficiency is the piano.  His daughter is a very accomplished cellist who makes her living as the director of a high school orchestra that consistently kills at competitions.
Closer to home, my only musical talent is to be a passable tenor in the choir.  For years, I sang with a choral group that performed all over the DC area, including a number of gigs at The Kennedy Center.  As a high schooler, our son was a pretty good cellist, but he walked away from it in college and never really looked back.”

 

Although I wasn’t able to catch her in time, PJ Parrish is the sister team of Kris Montee and Kelly Nichols.

As for me, my maternal grandfather was a highly regarded artist (painter) in his time. My mother was a beautiful writer, even though I never knew it while she was alive. After she passed, I discovered notebooks full of her writing.

So, can creativity be passed through our DNA? Judging by this small pool of writers, I find it hard not to entertain the possibility.

I’m betting the same holds true if I expand the test subjects to include you, my beloved TKZers. How many of you have creative folks in your family tree?

On a picturesque fall morning in Grafton County, New Hampshire, a brutal murder rocks the small town of Alexandria. In the backyard of a weekend getaway cabin, a dead woman is posed in red-satin, with two full-bloomed roses in place of eyes.

In her hand, a mysterious envelope addressed to Sheriff Niko Quintano. Inside, Paradox vows to kill again if his riddle isn’t solved within 24 hours.

With so little time and not enough manpower, Niko asks his wife for help. But Crime Writer Sage Quintano is dealing with her own private nightmare. Not only did she find massive amounts of blood on the mountain where she and her family reside, but a phone call from the past threatens her future–the creepy mechanical voice of John Doe, the serial killer who murdered her twin sister.

Together, can Niko and Sage solve the riddle in time to save the next victim? Or will the killer win this deadly game of survival?

Pre-order for 99c and save! Releases July 25, 2018. Want an early peek? Read opening chapter HERE.

 

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6 Unusual Forensic Techniques

By Sue Coletta

The forensic community works tirelessly to improve techniques to aid law enforcement, and much of this work is done at body farms across the country. The Texas body farm has conducted some amazing work. I’ve complied my top six forensic advancements, which I think you’ll find fascinating.

Teeth Show Time of Death

When no clues exist to identify a corpse, investigators have a serious problem. The determination of age and sex of the body can be crucial to limit the search for individuals that could possibly match missing persons records. Today, gender can be determined through DNA, as well as the skeleton itself, but believe it or not, it’s not as accurate as testing done on teeth. Age estimation in children and adolescents often depends on radiological examination of skeletal and dental development. In adults, however, age estimation is much less accurate.

Enter: aspartic acid racemization and radiocarbon dating.

At the sprawling 26-acre Freeman Ranch in Texas, over 50 human corpses reside at the body farm. Many of which are checked via drone. Scientists examined 44 teeth from 41 individuals using aspartic acid racemization analysis of tooth crown dentin and radiocarbon dating of enamel. Of those, ten were split and subjected to both radiocarbon and racemization analysis. Combined analysis showed that the two methods combined worked better than relying on one or the other.

Radiocarbon Dating, a forensic tool also done on eyes, is an accurate way to determine environment, date of birth, age of deceased, nutrition, diet, and even date of death. I’ve written about Radiocarbon Dating before (see link above). Briefly, similar to counting rings on a tree to determine its age, same applies to the eyes and teeth. Only with teeth researchers aren’t looking for crystallins.

Twice a year each permanent tooth is anchored to the gums by tiny, distinct fibers. A bright line is laid in the spring or summer, depending on where you live, and a dark line in the fall or winter. The number of bands, as well as the color and width of the outermost ring, help scientists estimate the deceased’s age at death and also narrows the TOD (time of death) window.

Plants and Trees Love Dead Bodies

Human remains act like any other type of fertilizer, producing nitrogen that leeches into the soil. and provides nutrients to plant-life. Trees and plants thrive on this added nutrient, growing taller, fuller, and greener than those not living near the dead. By studying their size compared to other plant-life in the area, experts can determine where and when bodies were buried.

Insects, Rats, and Squirrels Help Determine Date of Death

I’ve written about entomology before, but did you know scavengers — like rats and squirrels, for example — prefer different types of human bones? It’s true. Rats like their bones greasy, and tend to chew on the ends in order to gain access to the marrow. Scientists can then look for these signs to determine how long the body has been in its earthly grave.

Conversely, squirrels prefer drier, more brittle bones that have been fully exposed to the elements. They use the calcium in bone to aid in the breeding of strong litters. By examining the different bite marks and narrowing when the bites occurred and by whom, forensic anthropologists are then able to determine if the body was skeletonized while fully exposed to the elements = squirrel activity. Or if buried in a shallow grave with nibbles on the ends of the bones = rats. Also, they can estimate how long the body has been dead and if the body has remained undisturbed.

Quick fun fact: it takes vultures only a few hours to strip a body down to bare bones — a time frame previously estimated to be weeks.

Mosquitos Can Aid Investigators

In bodies that are badly degraded obtaining DNA becomes a chore, and sometimes isn’t possible at all. Researchers at the body farm, however, have a solution. Mosquitos and other biting insects, believe it or not, preserve portions of the DNA in the bodies they feed on. By trapping and dissecting these insects, DNA could be recovered.

How cool is that? It’s also a bit disturbing to think of mosquitos flying around with our DNA inside them. Or worse, when you smack a mosquito and it leaves a trail of blood, someone else’s DNA could be splattered on your palm. Yuck! I swear, the more I learn, the more paranoid I become. I don’t know about you but these things haunt me. LOL #writerslife

Decomposition Follows a Set Process

The body farm discovered a set pattern to decomposition. One week exposed to open air equals two weeks in the water and eight weeks buried underground. The latter refers to murdered victims, not people who’ve been embalmed or mummified. Environment, temperature, clothing, and weather all have to be taken into account as well, but as a baseline this formula aids investigators a great deal.

Drones Help Find Buried Remains

In bodies not visible to the naked eye, drone flights are part of an ongoing study using near infrared imaging to detect bodies above and below the ground. This technology can also spot locations, where a corpse was previously buried for up to two years after its removal.

“The search for clandestine bodies is a very time-consuming ordeal,” Wescott told the Texas Tribune. “Even then, a lot of times you can walk right by them and not realize that they’re there.”

As corpses decay, they release carbon and nitrogen into the soil, which decreases the amount of light the soil reflects. The influx of chemicals first kills plants, but as it disperses into the soil around the body it morphs into a fertilizer that reflects a ton of light. By using near infrared imaging the drones can detect these reflections. Two extremes show up as black and white on the mostly gray near infrared imagining. Anyone searching for a body doubles their chances of finding it.

Cool, right?

Have you found a fascinating forensic technique in your research? Did you use it in a story?

Wishing all of you a safe and happy 4th of July! Stay cool.
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Can they crack the riddles in time to save the next victim?

I’m excited to announce my new release, SCATHED, is now available for pre-order. Only 99c. Yay!!!

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