Pleeblandia

Thoughts from the front lines


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The Scarcity of Human DNA

         Atwood’s finale to the MaddAddam Trilogy focuses on how the remaining group of humans survive the everyday struggles of a post-Flood world. This lack of survivors arises as a major issue for the survival of the human race, as their small number in size does not reach the minimum needed to viably repopulate the Earth.

         Back in 2002, anthropologist John Moore asked himself the following question: How many humans would it take to survive a 2000-year long trip to another solar system? In an attempt to solve this question, Moore postulated that a minimum of 160 humans would be sufficient to generate a stable and healthy population. More recently, anthropologist Cameron Smith tackled the same question and estimated that such a starship would have to carry at least 10,000 people.

         With this in mind, do the MaddAddamites and Gardeners stand any chance of keeping the human race afloat? Surely not. It’s pessimistic to say, but it is the harsh truth. For years, biologists have observed isolated animal populations whose numbers were initially incredibly low, like in the case of the platypuses (yes that’s plural for platypus) of King Island, found in the Bass Strait between Australia and Tasmania. A team of biologists sampled 18 individuals and found very little genetic diversity among them:

“Currently, genetic diversity in King Island O. anatinus is severely depauperate and the population is likely to be suffering from reduced fitness, reduced evolutionary potential, and an increased risk of extinction.” (Furlan et al., 2012)

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Simulated declining of genetic diversity among Kangaroo Island platypus populations. The black diamond represents the populations as of 2012. (Furlan et al., 2012)

The article offers solutions to this increased risk of extinction:

“To maintain adaptive potential and minimise the risk of extinction (Reed and Frankham 2003), levels of genetic diversity need to be maintained (in the case of Kangaroo Island) or ideally, increased. (…) Increasing the total population size through population range expansion can slow the loss of genetic diversity.” (Furlan et al., 2012)

Note: Kangaroo Island had the same problem as King Island. The study observed populations from both islands. 

         And so, the increasingly small group of MaddAddam survivors probably won’t be passing on the torch anytime soon. Unlike the platypuses of King and Kangaroo Island, humans can’t intervene and simply add more genetic diversity, and the survivors aren’t doing themselves any favors either. Not only did they off two Painballers with perfectly good DNA, essentially removing their genes from the gene pool, but Zeb also got himself killed on a trip out in the wild and indirectly caused Toby to die as well.

         4 humans down at the end of the novel, and the survivors are congratulating Swift Fox for having Craker babies instead of Painballer babies. It seems like Crake’s master plan worked after all. With human-Craker babies now in the mix, will the presence of human DNA in Craker populations drive the Crakers to suffer the same fate?

Read More:

Popular Mechanics – “How Many People Does It Take to Colonize Another Star System?

PubMed, NCBI – “How is extinction risk related to population-size variability over time? A family of models for species with repeated extinction and immigration.

 


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OrganInc: Fact or Fiction?

Behind Compound walls lies OrganInc Farms, a research facility dedicated to growing human tissue organs in pigoon hosts (or as the scientists might call them, sus multiorganifier). But is OrganInc simply a figment of Atwood’s imagination, or is it based off of a scientific reality?

According to the U.S Department of Health & Human Services, approximately 119,000 people – men, women and children alike – are on the U.S national transplant waiting list. In 2015, only 30,970 people were treated, and the number of people needing an organ transplant is ever growing. With so few organs being donated, research scientists have resorted to implanting human stem cells in animals to tackle this issue.

Biologically speaking, these animal hosts are really called “chimeras,” that is, “an organism containing a mixture of genetically different tissues, formed by processes such as fusion of early embryos, grafting, or mutation.” Chimeric animals have been around for a while – scientists were producing chimeric mice in the 80s, hybridizing two species together, but have only recently begun experimenting with pigs.

Just a few months ago, in January, researchers at the Salk Institute for Biological Studies came out with a report detailing the growth of human-pig embryos – the first of its kind. They accomplished this feat by injecting human cells into a pig blastocyst, the earlier form of the embryo, and letting it grow in-vitro. Though the resulting embryo did not live for more than four weeks, Belmonte and his team made a large leap towards the approaching reality of interspecies organ transplants.

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An illustration of the potential process for producing human organs in pigs. (Cell Press)

For the time being, pigoons still only live in Atwood’s MaddAddam trilogy, but with recent advances in animal chimerism and the advent of CRISPR as a gene editing tool, pigoons will soon be a reality. Ethics aside, the need for more organs is and will continue to be a pressing issue for the coming years. 22 people die everyday due to the severe lack of donated organs in circulation. Is modern biology up to the task? One thing is for certain: OrganInc Farms is not as farfetched as it is made out to be.

Read more:

“Scientists Create First Human-Pig Chimeric Embryos” – BBC News

“Scientists create a part-human, part-pig embryo – raising the possibility of interspecies organ transplants.” – The Washington Post

References:

Simone van den Berg, Header photo (pig)

Wu et al., Creating human-pig chimera embryos illustration