What’s the procedure that promises to deliver babies unaffected by the genetic abnormalities of their parents? It’s called heritable genome editing (HE) or germline editing and uses “gene editing” technology.
Currently, the fastest, cheapest and most reliable technique to edit genes is the CRISPR-Cas9 system.
Think of CRISPR-Cas9 system as pair of molecular scissors that has been programmed to edit a specific portion of DNA. Cas9 is a protein that can cut double-stranded DNA. It is coupled with an RNA sequence programmed to find the DNA sequence to be edited. When that target DNA is found, Cas9 binds to the DNA and cuts it, which shuts off the targeted gene.
CRISPR
The ability to use CRISPR for gene editing has changed the way scientists approach the treatment of diseases caused by changes in a single gene. But it’s important to distinguish between two types of gene editing: somatic gene editing and heritable gene editing.
Somatic gene editing affects only certain cells in a person in a way that does not impact reproductive cells. For example, a 36-year-old patient, Victoria Gray, suffering from sickle cell disease has had cells drawn from her bone marrow. Those cells were treated using CRISPR and then infused back into the patient. These edited cells produced a protein that helped alleviate the symptoms of sickle cell and improved the patient’s quality of life. But these changes would not be passed down to any child she subsequently had.
Victoria Gray, who has sickle cell disease, volunteered for one of the most anticipated medical experiments in decades: the first attempt to use the gene-editing technique CRISPR to treat a genetic disorder in the United States. Meredith Rizzo/NPR
In contrast, heritable genome editing (HGE) is the process by which human reproductive cells (sperm, egg cells) or embryos are “edited” with the goal to produce children. These changes in the genetic make-up of reproductive cells are passed down from generation to generation.
However, HGE carries safety risks and raises ethical questions, what some have called the “dark side of CRISPR”.
From a safety standpoint, the editing can cause unintended changes, such as the loss of an entire chromosome or big portions of it, which can doom the life of any child born with such edits.
Also, the use of HGE elicits ethical questions about the value of human life. It can cut people with disabilities out of existence—at the embryonic stage—without the rest of humanity even noticing. Although society at large may view genetic “perfection” as an undeniable good, many people with disabilities (for example several in the hearing-impaired community) are very protective of their genetic differences. Each human is intrinsically worthy of life just as he or she is.
In addition, the future child who possesses edited genes will have a genome to which he or she has not consented. Even with technological refinements to minimize unintended gene edits, do parents have the right to decide the genetic make-up of their future children and grandchildren?
From a regulatory standpoint, who would decide which genes are worth keeping and which ones should be removed from the human pool? “Society at large”? Agencies like the FDA? Scientists? Doctors?
At the moment, HGE is illegal throughout the world. But this regulatory prohibition has not stopped a scientist from experimenting on embryos using CRISPR. Twin babies, Lulu and Nana, were born from that experiment.
This week, I’ll be micro-blogging about heritable gene editing, i.e. the process by which human reproductive cells (sperm, egg cells) or embryos are “edited” to produce children.
The primary question is this:
The story is familiar but with a twist.
Boy meets girl. They fall in love and get married.
Among their wedding gifts is a DNA ancestry kit. Out of curiosity, they submit their DNA samples. Results return with the information that they are each “carriers” for an autosomal recessive disorder. This means that although they do not have health problems, they each “carry” one copy of the abnormal gene. There’s a 50% chance that their children will also be “carriers” (the two middle babies in the below chart) and a 25% chance that they’ll have a child who carries both copies of the abnormal gene and suffers from the disease (purple baby in the below chart).
Autosomal Recessive Disorder
If you were in this couple, would you avail yourself of a procedure that promised to edit out the abnormality in your genes so all your potential children would be neither “carriers” nor sick?
A couple of nights ago, Hero Boy came to our bedroom, sobbing.
Earlier in the evening, electricity had gone on and off in the neighborhood. As a result, the circuit breaker had tripped in the middle of the night, interrupting the supply of power to the upstairs bedrooms.
Hero Boy, who’d fallen asleep to the comforting glow of a night lamp, had awoken to obscurity. Rightfully terrified, he’d rushed to us.
My husband resolved the breaker issue and Hero Boy went back to sleep in his room.
That little nighttime episode was a reminder of how we are instinctively drawn to the light. It is comfort, it is clarity, it is a blessing.
God himself said it after He spoke the light into existence. “And God saw the light, that it was good.” (Genesis 1:4)
Without light, creation would have remained shrouded in darkness (“darkness was upon the face of the deep.” Genesis 1:2)
Light is exactly as God intended it to be, even when we take it for granted.
Sadly, there are somber times when we can’t just flip a switch and illuminate a room. Or push a button to release lifesaving warmth.
As parts of Florida are battered by hurricane Ian, let’s pray for those residents whose lives have been upended. Prayers that visible light and power will be promptly restored, that damage will be minimal, and that those stranded will be rescued.
We can also help bring God’s light to affected communities by supporting organizations providing hurricane relief such as Samaritan’s Purse or Save the Children.
Likewise, as Europeans (and probably many U.S. families) brace themselves for a cold, dark winter, let’s pray for God’s protection.
Picture this. You’re in bed. The thermostat is set to your desired comfort temperature. Your preferred source of white noise hums in the background. The bedsheets are crisp and clean. Yet, sleep eludes you. You try counting sheep, but they dance away, their hooves leaving fading imprints on the repetitive thought du jour.
If that scenario is the unfortunate blueprint for most of your nights, you’ve got company.
Repetitive Thinking*
Person caught in a cycle of repetitive thinking
Repetitive thinking is the process of thinking attentively, repetitively, or frequently about oneself and one’s environment. Two types of nighttime repetitive thinking are believed to play a role in insomnia: worry and rumination.
“But…it’s productivity, not worry!”
If like me, you consider yourself a Very Efficient PersonTM, you might be chafing at having nighttime planning or problem-solving labeled as “worry”. After all, you’re not wringing your hands; you’re making good use of time. There might be new responsibilities at work or an uncomfortable conversation to be had with a friend or relative. Writers, you might be working out the kinks of a certain difficult scene. Thus, planning or problem-solving, given your sleeping troubles, is merely being productive, right?
Worry is a coping strategy for planning or problem-solving that focuses the mind on future threats and uncertainties.
No. It is worry.
What about rumination?
Worry contemplates the future and rumination dredges up the past.
Rumination is a coping strategy that involves dwelling on the past to understand and, potentially, alleviate negative emotions. Do you replay the moment when you made a mistake during a workplace presentation? Do you analyze a prior communication and brainstorm more suitable words than the ones you offered? Most of us have done so.
Whether as worry or rumination, repetitive thinking is a whirlpool in which your preoccupations swirl without ending.
“Just Thinking” or Preparing to Outrun a Tiger?
The exact mechanisms by which nighttime repetitive thinking disturbs sleep are poorly understood. Even so, we now know some of the effects of nighttime repetitive thinking on the body (as opposed to the mind).
Evidence suggests that nighttime repetitive thinking places enough strain on the brain to prevent the automatic inhibition of wakefulness that occurs around sleep onset. So, thinking about that spreadsheet or to-do-list, since you can’t sleep, keeps your body alert, which is incompatible with sleep.
Nighttime repetitive thinking also increases the heart rate and leads to elevated evening levels of cortisol, a hormone that is mainly released at times of stress.
Therefore, through repetitive thinking, the body enters a state similar to the biological basis for the “fight or flight” response. You’re in bed, yet your body is bracing for an attack from an invisible tiger.
Interrupting the Vicious Cycle
Bird escaping from a cage
Clinical studies indicate that mindfulness-based techniques alleviate rumination and worry.
Mindfulness is defined as techniques for “maintaining a moment-by-moment awareness of our thoughts, feelings, bodily sensations, and surrounding environment, through a gentle, nurturing lens.”
Evidence indicates that aspects of repetitive thinking such as self-blame (rumination), and fear and uncertainty (worry) are ideal targets for mindfulness-based interventions, which emphasize non-judgment, acceptance, letting go, trust, non-striving, etc.
However, it is my belief that mindfulness separated from biblical truth is merely a tug of war between “positive thinking” and “negative thinking”. Eventually, one’s supply of “good vibes” will run dry.
God’s Promises
Opened Bible
God tells us in the Bible how to handle worry and rumination. Here are some examples:
Worry
“Therefore, do not worry about tomorrow, for tomorrow will worry about itself. Each day has enough trouble of its own.” (Matthew 6: 34)
That spreadsheet, scene, or other burden that squats in your mind at nighttime can be dealt with the next day.
Further, this is what the prophet Jeremiah says about God’s faithfulness in Lamentations 3:22-24:
“Because of the Lord’s great love, we are not consumed, for His compassions never fail.
They are new every morning; great is Your faithfulness.
I say to myself, “The Lord is my portion; therefore, I will wait for him.'”
Why strive on your own when you could receive a new provision of God’s mercies the next morning? Even if you don’t have a lightbulb moment that illuminates your problem or provides a new perspective, waking up with a refreshed rather than a battered mind is a mercy.
And on a pragmatic level (for my fellow Very Efficient PeopleTM), Jesus said it best by asking in Luke 12:25:
“Who of you by worrying can add a single hour to your life?”
Ouch! Nighttime repetitive thinking has only left me with daytime misery, dark circles, and probably a shortened life expectancy.
We’re invited to cast our cares on the Lord (Psalm 55:22) and He will sustain us; to put our trust in Him when we’re afraid (Psalm 56:3); and to trust in Him with all our hearts and not lean on our own understanding (Proverbs 3:5-6).
Rumination
As to rumination, churning thoughts of self-condemnation is succumbing to the lie that you’re worthless, unforgivable, and forever stained by sin.
However, God’s Word gives us the truth. He forgives all of our sins (Psalm 103:3), redeems our lives from the pit, and crowns us with love and compassion (Psalm 103:4). He has removed our transgressions so far from us as the east is far from the west (Psalm 103:12).
Above all, Jesus Christ has already paid the price for the sins of those who have faith in Him.
“God made Him who had no sin to be sin for us, so that in Him we might become the righteousness of God.” (2 Corinthians 5:21)
Self-condemnation attempts to diminish Christ’s atonement of our sins.
So, stop rewinding the tape and cling firmly to God’s promise that there is now no condemnation for those who are in Christ Jesus. (Romans 8:1)
I hope and pray you have a night of sleep devoid of repetitive thinking.
* There’s new evidence that in addition to rumination and worry, invading thoughts also play a role in sleep disturbance. Unlike repetitive thoughts, invading thoughts burst into the mind and trigger anxiety spikes.
Sources:
(1) Bible verses are from the New International Version. (2022). BibleGateway.com. http://www.biblegateway.com/versions/
(2) Pillai V, Drake C. 2015. Sleep and Repetitive Thought: The Role of Rumination and Worry in Sleep Disturbance. In: Babson K, Feldner M, editors. Sleep and Affect. Academic Press. p. 201-225.
(3) Lancee J, Eisma M, Van Zanten K, Topper M. 2017. When Thinking Impairs Sleep: Trait, Daytime and Nighttime Repetitive Thinking in Insomnia. Behavioral Sleep Med. 15(1): 53-69.
(4) Melo J, Campanini M, Souza S, Andrade S, González A, Jiménez-López E, Mesas A. 2021. Work-related rumination and worry at bedtime are associated with worse sleep indicators in school teachers: a study based on actigraphy and sleep diaries. Sleep Med. 80:113-117.
