Rosa Rubicondior: Creationism Refuted - Complex Evolution Of The Sweet Potato

Sunday, 10 August 2025

Creationism Refuted - Complex Evolution Of The Sweet Potato

‘Tanzania’ sweetpotato variety.

Credit: Benard Yada, National Crops Resources Research Institute
(NaCRRI), Uganda.

Decoding Sweetpotato DNA: New Research Reveals Surprising Ancestry - Boyce Thompson Institute

Despite abundant evidence to the contrary, creationists often claim that mutations cannot create new genetic information.

This argument rests on a deliberate misrepresentation of Shannon information theory, developed by Claude Shannon to optimise the transmission of information. Shannon’s theory equates information with entropy (a measure of uncertainty), not with “meaning”, and it draws on mathematical principles that can be related to thermodynamics. In thermodynamics, energy is conserved—neither created nor destroyed.

Creationists then assume, incorrectly, that this means the “information” in a genome cannot be created. They also tend to overlook the fact that, if their analogy with energy held true, it should also be impossible to destroy genetic information—yet they have no difficulty accepting the latter.

Why Shannon Entropy Does Not Equate to “Meaning”. Shannon information theory was developed for engineering problems — specifically, how to transmit messages accurately through noisy channels. Its “information” is a measure of uncertainty or surprise in a sequence, based on the probability of each symbol.

Key points:

No semantics: Shannon’s measure says nothing about whether a sequence is meaningful. The string “XQZPJ” and the string “HELLO” can have the same Shannon information content if they are equally unlikely in the source language.
Context-free: Shannon entropy depends only on symbol probabilities, not on the message’s interpretation. This is why a random jumble of letters can have high Shannon information even if it’s nonsense.
Physical link: Mathematically, Shannon’s measure resembles thermodynamic entropy, but this is an analogy, not an identity. Shannon entropy is not “energy”, and it is not bound by the same conservation laws as physical energy.

When creationists conflate Shannon information with biological “meaning” or “genetic instructions”, they commit a category error: they treat a mathematical measure of uncertainty as if it were a semantic property of DNA. In reality, the functional value of a DNA sequence — whether it benefits, harms, or does nothing for an organism — depends entirely on the environment in which it is expressed.

Sweet Potatoes – Ipomoea batatas.

Taxonomy & Family

Belongs to the family Convolvulaceae (morning glory family), which is mostly tropical vines and herbaceous plants.
Ipomoea is a large genus (over 600 species), but I. batatas is the only one of major agricultural importance.
Despite the name, sweet potatoes are not closely related to true potatoes (Solanum tuberosum), which are in the Solanaceae (nightshade family).

Origins & Domestication

Native to tropical Central and South America.
Archaeological evidence shows cultivation at least 5,000 years ago, with some estimates pushing it to 8,000–10,000 years in Peru.
Polynesian explorers carried sweet potatoes across the Pacific to islands such as Hawaii and New Zealand centuries before European contact — linguistic evidence (the Polynesian word kumara) supports this.

Genetics

Hexaploid — it has six sets of chromosomes, which is rare in major crops.
Genome size: ~2.9 gigabases.
Origin story:

Likely arose from hybridisation and polyploidy events involving wild Ipomoea species.
Whole genome duplications have provided raw material for evolutionary innovation — duplicated genes can mutate to take on new functions while the originals keep their old ones.

Recent study (Fei et al., 2025, Nature Plants) shows:

Three ancestral species contributed to the modern sweet potato genome.
One of these is still living (I. trifida), which is closely related to sweet potato.
Polyploidy and subsequent adaptation were key in giving sweet potatoes their diverse traits — from tuber storage to disease resistance.

Nutritional Profile

Rich in beta-carotene (especially orange-fleshed varieties), a precursor to vitamin A.
Good source of fibre, vitamin C, potassium, and antioxidants.
Lower glycaemic index than regular potatoes, meaning a slower impact on blood sugar.

Agricultural Importance

Cultivated in more than 100 countries.
Top producers: China, Malawi, Nigeria, Tanzania, and Indonesia.
Particularly important in food security in sub-Saharan Africa — orange-fleshed varieties are promoted to combat vitamin A deficiency.

Biology & Adaptations

Tuber formation: Storage roots swell with starches and sugars — an adaptation for energy storage.
Clonal propagation: Farmers often plant vine cuttings, not seeds.
Broad ecological tolerance: Can be grown in poor soils and withstand drought better than many staples.

Fun Facts

Sweet potatoes were grown in space: NASA tested them as a sustainable food source for long-term missions.
Their colour varies — white, yellow, orange, and even purple-fleshed varieties exist. Purple ones contain anthocyanins, powerful antioxidants.
They’ve been tangled in a naming mess: In the US, orange sweet potatoes are often (incorrectly) called “yams” — true yams are Dioscorea species from Africa and Asia.

What they fail to appreciate is the nature of information in a genome. None of them has ever produced a rigorous, measurable definition of “genetic information” that works across biological contexts. In reality, as evolutionary biology recognises, the functional meaning of genetic information depends entirely on the environment in which it is expressed.

For example, a mutation enabling a bacterium to metabolise plastics as an energy source would have been useless — or even harmful — a hundred years ago, when plastics were absent from the environment. Today, the same mutation would be highly advantageous. The “meaning” of the genetic change is determined by environmental context.

To illustrate with a written-language analogy, compare the strings “INFORMATION” and “TEAVE”. Do they contain the same amount of information? Do they have different meanings, or is one just meaningless “junk”?

For an English speaker, the answer is obvious: “INFORMATION” has a clear meaning, whereas “TEAVE” is nonsense — perhaps a typo for “LEAVE” or “BEAVER”. But to an Estonian, the situation is reversed: “INFORMATION” is meaningless, but “TEAVE” means “information”. The sequence of characters only gains meaning in the right linguistic environment. Likewise, DNA sequences gain biological meaning only in the right environmental context.

Adding new DNA to a genome—or substituting one nucleotide for another—does not add information in the Shannon sense, because Shannon’s framework does not measure “meaning” and because the atoms and molecules in the new DNA are not created from new energy. There is therefore no violation of thermodynamic principles.

This discussion of how creationists misuse Shannon information sets the stage for a clear example of how new biological information can arise through purely natural processes: gene or whole-genome duplication followed by divergence via mutation and selection. Such a process is well illustrated in the important food crop, the sweet potato (Ipomoea batatas).

The genome of the hexaploid sweet potato is the subject of a recent paper in Nature Plants by a team led by Professor Zhangjun Fei at the Boyce Thompson Institute (BTI), as well as a news release from the BTI.

Decoding Sweetpotato DNA: New Research Reveals Surprising Ancestry
The sweetpotato feeds millions worldwide, especially in sub-Saharan Africa, where its natural resilience to climate extremes makes it crucial for food security. But this humble root vegetable has guarded its genetic secrets for decades. Now, scientists have finally decoded its complex genome, revealing an intricate origin story and providing powerful tools to help improve this vital crop.
Sweetpotato DNA is extraordinarily complex. While humans have two sets of chromosomes, one from each parent, sweetpotatoes have six. This condition, called hexaploidy, made deciphering their genetic code like trying to reconstruct six different, yet similar, sets of encyclopedias that have been shuffled together.

A team led by Professor Zhangjun Fei at the Boyce Thompson Institute achieved a significant breakthrough, as reported in Nature Plants. Using cutting-edge DNA sequencing, along with other advanced techniques, they created the first complete genetic makeup of ‘Tanzania’—a sweetpotato variety prized in Africa for its disease resistance and high dry matter content.

The central challenge was to untangle the plant’s 90 chromosomes and organize them into their six original sets, called haplotypes. The team succeeded in fully separating, or ‘phasing,’ this complex genetic puzzle, something that had never been achieved before.

Having this complete, phased genome gives us an unprecedented level of clarity. t allows us to read the sweetpotato’s genetic story with incredible detail.

Professor Zhangjun Fei, senior author, Boyce Thompson Institute
Cornell University, Ithaca, NY, USA.

The research revealed surprising complexity. The sweetpotato genome is a mosaic assembled from multiple wild ancestors, some of which have yet to be identified. About one-third comes from Ipomoea aequatoriensis, a wild species found in Ecuador that appears to be a direct descendant of a sweetpotato progenitor. Another significant portion resembles a wild Central American species called Ipomoea batatas 4x, though the actual donor may still remain undiscovered in the wild.

Unlike what we see in wheat, where ancestral contributions can be found in distinct genome sections, in sweetpotato, the ancestral sequences are intertwined on the same chromosomes, creating a unique genomic architecture.

Shan Wu, first author.
Boyce Thompson Institute
Cornell University, Ithaca, NY, USA.

This intertwined genetic heritage means that sweetpotato can be tentatively classified as a “segmental allopolyploid”—essentially a hybrid that arose from different species but behaves genetically as if it came from a single one. This genomic merging and recombination gives sweetpotato its remarkable adaptability and disease resistance, traits crucial for subsistence farmers worldwide.

The sweetpotato’s six sets of chromosomes also contribute to its enhanced resilience. With multiple versions of important genes, the plant can maintain backup copies that help it survive drought, resist pests, and adapt to different environments—a feature known as polyploid buffering.

Professor Zhangjun Fei.

However, achieving a full understanding of sweetpotato’s genetic potential will require decoding multiple varieties from different regions, as each may carry unique genetic features that have been lost in others.

The work by Fei and his team represents more than just an academic milestone. Equipped with a clearer understanding of sweetpotato’s complex genetics, breeders can now more efficiently identify genes responsible for key traits like yield, nutritional content, and resistance to drought and disease. This precision could accelerate the development of improved varieties.

Beyond sweetpotato, this research demonstrates how modern genomic tools can help decode other complex genomes. Many important crops, including wheat, cotton, and banana, have multiple sets of chromosomes.

As climates shift and pest and disease pressures increase, understanding these genetic puzzles is critical for breeding resilient crops and addressing challenges in food security.

Publication:
Wu, S., Sun, H., Zhao, X et al.
Phased chromosome-level assembly provides insight into the genome architecture of hexaploid sweetpotato. Nat. Plants (2025). https://doi.org/10.1038/s41477-025-02079-6

Abstract
The hexaploid sweetpotato (Ipomoea batatas [L.] Lam.) is a globally important stable crop that plays a key role in biofortification. Its high resilience and adaptability provide distinct advantages in addressing food security and climate challenges. Here we report a haplotype-resolved chromosome-level genome assembly of an African cultivar, ‘Tanzania’, revealing mosaic genomic origins along haplotype-phased chromosomes. The wild tetraploid I. aequatoriensis, currently found in coastal Ecuador, contributes to a substantial fraction of the sweetpotato genome. Another large proportion of the genome shows a closer genetic relationship to the wild tetraploid I. batatas 4×, distributed in Central America. The sequences contributed by different wild species are not distributed in typical subgenomes but are intertwined along chromosomes, possibly owing to the known non-preferential recombination among sweetpotato haplotypes. This study improves our understanding of sweetpotato origin and genome architecture and provides valuable genomic resources to accelerate sweetpotato breeding.

Wu, S., Sun, H., Zhao, X et al.
Phased chromosome-level assembly provides insight into the genome architecture of hexaploid sweetpotato. Nat. Plants (2025). https://doi.org/10.1038/s41477-025-02079-6

© 2025 Springer Nature Ltd.
Reprinted under the terms of s60 of the Copyright, Designs and Patents Act 1988.

This study on the sweet potato genome provides a textbook example of how new genetic information arises naturally. The modern sweet potato (Ipomoea batatas) is a hexaploid — it carries six full sets of chromosomes, the result of multiple ancient whole-genome duplication events involving at least three different ancestral species.

First, two species hybridised to produce a tetraploid ancestor. Later, this tetraploid hybridised again with a diploid species, producing the modern hexaploid sweet potato. These were genuine speciation events, but they could not have been “witnessed” at the time, because no one would have known that the hybrids involved would go on to form stable, reproductively distinct populations. Only with hindsight can we recognise that speciation had occurred.

Whole-genome duplications supply vast amounts of raw genetic material. Duplicated genes are freed from the constraints of their original functions, allowing ordinary mutation and natural selection to act on them. Over time, some acquire entirely new or modified roles — adding genuinely new functional information to the genome. In the sweet potato’s case, many duplicated genes have been repurposed for traits such as disease resistance, tuber development, and environmental adaptation.

Creationists claim that mutation can only degrade genetic information, but the sweet potato’s history shows the opposite. Here we see multiple rounds of duplication followed by innovation, producing a highly successful crop plant with complex new traits — all through natural processes, without any need for an external “designer”.

In summary: The sweet potato (Ipomoea batatas) is living proof that new genetic information and new species can arise naturally. Its genome shows two ancient hybridisation events — first producing a tetraploid ancestor, then a hexaploid species — followed by millions of years of mutation and selection acting on duplicated genes. Many of these genes have since evolved entirely new functions, giving the plant complex traits such as disease resistance and enhanced storage roots. Far from degrading genetic information, this process created it — directly contradicting the creationist claim that mutation cannot produce anything new.

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