Pleeblandia

Thoughts from the front lines

The Scarcity of Human DNA

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         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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3 thoughts on “The Scarcity of Human DNA

  1. I was thinking the exact same thing all throughout the third book! During the third book, as bad as it sounds, I kept thinking to myself “why is it worth it everyone is going to die anyways!”. As sad as I was, I also thought that in the end, Crake did end up succeeding in erasing the human race. However, I think that Atwood was trying to tell us that not everyone had died with the waterless flood like we were lead on to believe. For example, Zeb died because he found other people, so how many is there out there? Maybe she was trying to give us some hope? Even if that is true, we all agree that for the human race to survive they have to stop killing each other, it is quite frustrating.

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  2. Interesting topic! Margaret leaves a great question that what happens to the post-flood world and the human future with the birth of the human-Craker babies? Margaret leaves a space for imagination and we can suggest many possible answers according to the clues that she had left in the books. I found that the second pregnancy of Swift Fox may hint that human female can adapt to the Craker’s reproduce process. Therefore, the uncertain father system may probably be accepted to human society. Furthermore, we all know what happened to Ren and Amanda when they were kidnapped by the paintballers, and what happened at the night in the last chapter of the second book when the Crakers come. However, Ren and Amanda both give a birth to the mixed-blood babies. Is it a coincidence or does it hint that in the matter of reproduction, Craker’s genes are dominant—that their genes can easily defeat human male’s genes, thus they always get the chance of increasing their population?

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  3. Great post! I find it interesting that the numbers differ between the two anthropologists. On that note, I really don’t think the Crakers can survive on their own. There are too few of them, so even with the humans that are left, there wouldn’t be a very high chance of survival. Atwood might have wanted us to question and wonder about what the future of humanity would be like with new genes and human beings. Ultimately, it’s hard to believe that the Crakers will survive in the long run since they drop dead at 30, but with human DNA, they could potentially begin to evolve over the years.

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