The double helix revisited

‍Introduction

In mid-1953 three successive brief papers in Nature announced the discovery of the double helix structure for DNA. The first paper in the trilogy describes the structure, making brief reference to earlier unsuccessful attempts, and proclaiming that “The novel feature of the structure is the manner in which the two chains are held together by the purine and pyrimidine bases”,¹ and includes an almost insignificant drawing of a small ball-and-stick model at the lower left corner of the page. This paper foreshadows the experimental work that underpins the proposed structure, specifically mentioning the contribution of Maurice Wilkins and Rosalind Franklin. The second paper describes “in a preliminary way, some of the experimental evidence for the polynucleotide chain configuration being helical, and existing in this form when in the natural state”,² that evidence being obtained using X-ray diffraction. This paper includes the famous “photograph 51”,³ central to the later controversy centering on Franklin’s contribution, and – like the first paper – acknowledges the ‘stimulation’ of two colleagues (James Watson, Francis Crick) and the ‘discussion’ with other colleagues (including Rosalind Franklin). The third paper is the most technical of the trilogy and explores the X-ray evidence further, and concludes with an expression of gratitude “to Prof. J. T. Randal⁴ for his interest and to Drs. F. H. C. Crick, A. R. Stokes and M. H. F. Wilkins for discussion”.⁵ This mutual acknowledgement of the contribution of the participating scientists and the commonality of references (as noted in Table 1) used in the trilogy of papers might suggest there had been a cozy collaboration of scholars in the solution of a multi-faceted problem. However, any such inference was disrupted by the publication in 1968 of James Watson’s reminiscences of the research process that was associated with the scientific discovery.⁶ Thirty-five years later – with rather less controversy – Maurice Wilkins’ autobiography includes his perceptions of the same events.⁷ An important point here is that the same events are recalled and interpreted somewhat differently by each of Watson and Wilkins: in essence, each author has constructed his own history. Moreover, because Watson and Wilkins were participants in the events, their accounts might be considered more authentic than the narratives created by those – such as Maddox,⁸ Sayre,⁹ and Markel (see later) – who were neither present at the time nor familiar with either the scientific research involved in the project or its day-to-day conduct.¹⁰ This paper explores the discovery through sentiment analysis of biographies and reminiscences of the protagonists and through citation analysis of scientific papers that cited the original reports on the research.

‍Sentiment analysis

A chapter-by-chapter sentiment analysis of Watson’s essentially autobiographical book and section-by-section analysis of Wilkins’ autobiography, both show variations of sentiment¹¹ throughout (Fig. 1) that are reminiscent of a fictional quest (Fig. 2),¹² i.e., a series of setbacks, interspersed with interim successes, along a journey before the goal is achieved.

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Perhaps more significant in terms of the current reawakening of interest in the significance of Franklin’s contribution is the analysis of sentences and sections of narrative that are specifically related to the authors’ perceptions of the social behaviour and scientific practice of Franklin.  Fig. 3 shows that In Watson’s book, most of the text relating to Franklin is of negative sentiment, although it does become more positive towards the end of the book where he becomes rather more conciliatory towards her. By contrast, in Wilkins’ book the range of sentiment – also shown in Fig. 3 – is much greater: swinging from highly positive to highly negative.

Watson’s book, with its consistently negative perceptions of Franklin, recalls events when he was a mere 25 years old, and was written 15 years after the events related to the discovery of the structure of DNA. Wilkins was 12 years older than Watson, and his autobiography, with its ambivalent perceptions of Franklin, was published 50 years after those same events. Accordingly, it is hardly surprising that Watson’s and Wilkins’ perceptions of Franklin are different; moreover, just because they are different does not render as invalid either of the historical narratives.

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In the absence of an autobiography of Rosalind Franklin, her sister’s recollections of her might be considered an acceptable proxy. Rather than laying blame, Jenifer Glynn’s measured recollection of Rosalind Franklin strikes a balance – a compromise if you will – between the research environment’s gender bias and ‘misunderstandings’, and between Rosalind being ‘marginalized’ and the resulting increased ‘tensions’:

“… Her [Rosalind’s] story has been adopted by feminists as a symbol of a woman struggling and unacknowledged in a man's world. This would, I think, have embarrassed her almost as much as Watson's account would have upset her. It suited the feminism of the 1960s and 1970s to portray her as a victim of male dominance, but she would have thought of herself simply as a scientist whose achievements should have been judged on their own terms, not as a “woman scientist” striking a blow for the rights of women.

"It is hard to say how far Rosalind's difficulties at King's College were added to because she was a woman, as well as arising from misunderstandings and a basic personality clash. She certainly felt insulted when she found that the main dining room at King's, where scientists would meet for discussions over lunch or coffee, was open only to men; this un-Parisian attitude was hard to take even if not unusual in English colleges at the time. Never integrated into the life of the lab, she felt marginalized, in a way that may well have made her pricklier and more assertive, increasing the tensions.”¹³

The sentiment for the paragraph quoted above is negative (-60.5%), Glynn supporting the feminist perspectives put forward in the 1970s as the cause of Rosalind Franklin’s distress. Despite this, the overall sentiment for Glynn’s recollections is positive (+44.8%). For comparison, an overall negative sentiment (-37.0%) is obtained from a 2017 biography of Rosalind Franklin, written from a scientific perspective by Brian Halton (Fig. 4A).¹⁴ Reflecting the passage of time since the feminism of the 1960s and 1970s, Halton’s biography of Rosalind Franklin is also critical of the management of the scientific enterprise of the time (Fig. 4A), as are reviews of Maurice Wilkins’ autobiography by Paul Doty¹⁵ and by David Parry¹⁶ (Fig. 4B). Specifically, Parry considers Randall’s management of the research centre may have been adversely influenced by his personal career ambitions.

Citation analysis

As expected, the number of citations of all three papers decreases with time after publication, and all show at least one resurgence in the number of citations at some time after publication. The immediate consequences of the writing of these papers in terms of their impact on the scientific community can be gauged by considering the number of citations per year for the 1953-1973 period, i.e., the first 20 years after the papers were written (Fig. 5; see also Table 1). The number of citations of the paper by Watson and Crick is about double that for Franklin and Gosling’s paper, which, in turn, is about double that for Wilkins et al.’s paper. This might suggest that, based on the inferred impact of the various facets of the discovery, a ‘pecking order’ of the scientists involved is: Watson and Crick > Franklin and Gosling > Wilkins et al. This same order is apparent in the citations overall (Fig. 6).

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The papers that cite the trilogy papers are not solely concerned with DNA-related science and potential applications;¹⁷ a few of the later citations discuss technological applications, and a few are historical,¹⁸ philosophical, or sociological¹⁹ in focus. Fig. 7 shows this distribution for Watson and Crick’s paper (Trilogy paper 1) in its decadal anniversary years (i.e., 1963, 1973, …) and for Franklin and Gosling’s paper (Trilogy paper 3). The perennially contentious aspect of the DNA story relates not to the science itself, but to the social dynamics of the research group, and a small number of recent papers citing the Trilogy papers continue to explore aspects of this.²⁰
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The traditional approach to telling the story of the science is to base it on the research findings. In the case of the double helix story, this would imply a focus on the trilogy of scientific papers that announced the discovery,²¹ but it could include information about the few papers that Watson, Wilkins, Franklin, and Crick, themselves referred to, and evaluating the scientific impact of the papers, perhaps including reviewing the details contained in the subsequent citations of the trilogy papers referred to here.

The feminist legacy

On the 70^th anniversary of the publication of the trilogy of papers announcing the double helix structure for DNA it is hardly surprising that interest should once again be focused on Rosalind Franklin’s contribution to the discovery. In an April 2023 issue of Nature two historians are reported as having used “an overlooked letter and an unpublished news article, both from 1953” to make a case for Franklin to be an equal contributor, alongside Watson and Crick.²² This echoes the stance earlier advocated by biographers such as Maddox and Sayre, who viewed the story of the discovery of the structure of DNA through a feminist lens. A more recent book by medical historian Howard Markel, which also reaches the conclusion that contributions of these researchers to the discovery should be considered equal, introduces an anti-Semitic explanation for discrimination against Franklin,²³ a contention which is strongly disputed by one of the book’s reviewers.²⁴  That said, as mentioned earlier in this paper, post-feminist biographers seem to be hinting at poor management of the scientific enterprise as a cause of the problems during the discovery of the structure of DNA.

Lastly, from an educational perspective a recent study includes in its conclusions that:

“… stories describing Rosalind Franklin’s neglected contributions can be of significant value in raising student understanding of gender inequities in science and how the history of science is often (mis-)-represented. We suggest the inclusion of more stories about the contributions of women scientists ²⁵ has the potential to encourage more female students to participate in the course activities, enhancing more female students’ motivation of learning, encouraging more female students to go for a career in STEM Science, Technology, Engineering, Mathematics in the long term.”²⁶

Whatever merit there may be in this suggestion, there is unlikely to be a single authoritative narrative of science that includes aspects of the social and professional interactions of its participants. Moreover, continually politicising the sociology of science in this way has the potential to have a disruptive influence on science and the conduct of scientific research. Disruption has been argued as both beneficial or otherwise to science itself,²⁷ but whether a change in a scientific paradigm occurs rapidly (as inferred for a Kuhnian ‘revolution’),²⁸ as has been claimed for the discovery of DNA,²⁹ or in a slower more ‘ecological’ mode,30 it probably makes little difference to the science in the longer term.

In contrast, Islamic history provides examples of how readily disruption can spell the end of a period of scientific discovery. A particular example is the destruction of the infrastructure of science and culture and the loss of Islamic scientific knowledge at the hands of invading Mongols in the early thirteenth century: “Islamic civilization that had taken 600 years to build was being erased in a matter of weeks”.³¹ This included the destruction of the ‘House of Wisdom’ – effectively a combination of a university and a multidisciplinary scientific research centre, among its other civic functions – in Baghdad.³² Even though Islam survived the Mongol invasion to became the cornerstone of the politically powerful Ottoman empire, the glory days of Eastern science were never regained: the empire stagnated intellectually in the 1600s and 1700s,³³ while the European Enlightenment flourished.³⁴ A similar example of the consequence of abrupt societal disruption is the end of enlightened social services in Iran in 1979.³⁵  Accordingly, it might be prudent for potential disrupters of science – including chemistry – to reflect on the idiom: “Be careful what you wish for”.

The legacy of the discovery of the structure of DNA – a New Zealand perspective

Remembering the DNA researchers

The location of Maurice Wilkins’ childhood home is marked by a commemorative plaque outside one of Victoria University of Wellington’s buildings on Kelburn Parade (Fig. 8).³⁶

In 2006 the Centre for Molecular Discovery, which had been established in 2002 as a consortium of research groups at the University of Auckland was re-launched as the Maurice Wilkins Centre for Molecular Discovery. One of New Zealand’s Centres of Research Excellence, the Centre describes its mission as: “bringing together scientists from a range of disciplines and research institutions to target serious human disease. Accordingly, the centre serves as a virtual hub, or point of contact, for a broad range of scientific expertise in molecular biodiscovery.” The Centre’s work includes research into human diseases, building collaborative scientific networks, and educating the next generation of scientists,³⁷  and complements genomic related research being undertaken by other organisations and individuals.³⁸

DNA and the origin of Māori and Polynesian peoples

While there has been much research into DNA globally, an area that has a particular relevance to New Zealand is its application to ascertaining the origins of Māori and other Polynesian peoples, which is summarised in the following two statements:

“The first ancient DNA samples from Teouma in Vanuatu showed that all three of the individuals tested – all women – carried the ‘Polynesian motif’ and were genetically similar to indigenous populations from the Philippines and Taiwan….”³⁹; and

“…Aotearoa/New Zealand became the last major landmass to be permanently settled by humans… Complete mitochondrial genome sequences of the likely founding population of Aotearoa/New Zealand recovered from the archaeological site of Wairau Bar … represent complete mitochondrial genome sequences from ancient Polynesian voyagers and provide insights into the genetic diversity of human populations in the Pacific at the time of the settlement of East Polynesia.”⁴⁰

Although some researchers are cautious of this DNA-driven approach to ethnology,⁴¹ the Austronesian Migration Theory (largely developed on linguistic evidence⁴² and supported by phylogeography⁴³) also asserts that Māori are descended from the indigenous tribes of Taiwan, whose wide migration means that New Zealand and Taiwan share linguistic and cultural connections. These connections have been recently highlighted in a:

“ground-breaking special edition of the Māori literary journal Ora Nui published in 2021, in which writing and artwork by the Indigenous peoples of New Zealand and Taiwan are presented side-by-side. The resulting journal is a rich offering of short fiction, poetry, creative non-fiction, essays and visual art.”⁴⁴

Francis Crick, Rosalind Franklin, James Watson, and Maurice Wilkins could never have imagined that their discovery of the structure of DNA would have such a direct, on-going, and potentially profound influence on the understanding of the ethnography and culture of indigenous Aotearoa New Zealand.

Appendix 1: Themes of knowledge and culture

One of the striking features of Wellington’s Central Library built in the1930s is the line-up of aspects of knowledge and culture above each ground-floor window, along the full width of the façade (Fig. 9).

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As you might expect of a library, ‘Literature’ has pride of place above the public entrance to the building. During construction of the building, it was observed that: “The exterior design of the building is not ornate. Its simplicity of treatment helps to give it a dignified and pleasing appearance.⁴⁵ The whole of the exterior is being finished with a cement coat of sandstone, matching the colour of the Darley Dale sandstone⁴⁶ columns at the main entrance on the Mercer Street frontage”⁴⁷ but no mention was made at that time of the inscriptions in the panels above the windows. Such inscriptions are not without precedent. In the US state of New York, for example, the north and south sides of the Rundel Memorial Building, Home to the Rochester Public Library – opened in 1936 and built in “a modern interpretation of the Renaissance style” – are extensively inscribed, the headings of which are: Science, Art, History, Biography, Literature, Social Sciences, Religion, and Philosophy.⁴⁸ 

Appendix 2: Maurice Wilkins’ former childhood home – 30 Kelburn Parade, Wellington

30 Kelburn Parade was part of ‘Block 1’ – the first piece of land subdivided by the Upland Estate Company in the late 1890s. Known then as ‘Lot 10’, it was purchased by Charles Vaughan Kreeft in that year. Kreeft was one of the original directors of the Kelburn Bowling Club (then located on four lots adjacent to Lot 10, but after 1914 located further south along Kelburn Parade). The first house built on Block 1 appears to have been that on Lot 10, and was owned by C.V. Kreeft. Records show that Mrs Kreeft was living at Lot 10 (which became 30 Kelburn Parade) in 1916, Mr Kreeft in 1917, and E.C. Levvey (a barrister and solicitor, who had been called up for war service) in 1918. It thus appears that from 1918 the house, although owned by Kreeft, was tenanted, the Wilkins family living there from 1918 to 1923. C.V. Kreeft died in 1924, but by then he was living in Abel Smith Street in Wellington. 30 Kelburn Parade was sold in 1929, following the death of its then occupant Francis John George Holmes.⁴⁹ The sale notice read:

“The solidly built residence containing 8 large rooms (Fig. 10), sun porch, verandah and usual offices, motor garage, etc., on land 41ft 6in x 164ft, known as No. 30, Kelburn Parade…

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“The house comprises a large drawing room with alcove and double doors leading to dining-room 10ft x 17ft, breakfast room, 4 bedrooms and maid’s room, large kitchen, bathroom with porcelain bath and basin scullery and washhouse. It is fully equipped with e.l. electric hot point, splendid hot water system, gas stove, and range. Most substantially constructed of heart timbers and in excellent order throughout. The excellent situation of this house, opposite the Victoria College and within a short distance of the Kelburn Croquet Ground and Park, the cable car, and on the bus route will command itself to any purchasers requiring a Town House. It is a beautifully sunny spot, well sheltered from all prevailing winds. Immediate possession can be arranged. For further particulars, and arrangements to view, apply to J.H. Bethune and Co., Auctioneers.”⁵⁰

Acknowledgements

Many years ago, when I was a science student at Victoria University of Wellington, history lecturer Dorothy Crozier initiated my interest in the history and sociology of science. I have maintained this interest as an undercurrent to much of my research, and it has been complemented more recently by access to books on Islamic science and Middle Eastern history from the personal library of the late Susan Balog.

Notes and references

1. Watson, J.H.; Crick, F.H.C. A structure for deoxyribose nucleic acid. Nature 1953, 171, 737-738.
2. Wilkins, M.H.F.; Stokes, R.A.; Wilson, H.R. Molecular structure of deoxypentose nucleic acids. Nature 1953, 171, 738-740.
3. Sutton, B. The story behind “Photograph 51”. 14 April 2023. https://www.kcl.ac.uk/the-story-behind-photograph-51  (accessed 11 May 2023)
4. J.T. Randall was the director of the laboratory. Wilkins (2003, pp. 140-151; see Notes and References 7) considers that Randall’s letter to Franklin prior to her appointment misrepresented what her scientific tasks would be, and that this contributed to the ensuing discord between the scientists.
5. Franklin, R.E.; Gosling, R.G. Molecular configuration in sodium thymonucleate. Nature 1953, 171, 740-741.
6. Watson, J. The Double Helix – A Personal Account of the Discovery of the Structure of DNA. Penguin: London, 1968.
7. Wilkins, M. The Third Man of the Double Helix – The Autobiography of Maurice Wilkins. Oxford University Press: Oxford, 2003.
8. Maddox, B. Rosalind Franklin: the Dark Lady of DNA. Harper Collins: New York, 2002.
9. Sayre, A. Rosalind Franklin and DNA. Norton: New York, 1974.
10. A classic example of an anthropological investigation of a scientific research environment is: Charlesworth, M.; Farrall, L.; Stokes, T.; Turnbull, D. Life Among the Scientists: An Anthropological Study of an Australian Scientific Community. Oxford University Press: Melbourne, 1989.
11. The sentiment of text in this paper is determined using the online tool at https://monkeylearn.com/sentiment-analysis-online/  (accessed 11 May 2023)
12. The ‘quest’ is one of several types of fictional narratives identified by Booker, C. The Seven Basic Plots: Why We Tell Stories. Continuum: London, 2004.
13. Glynn, J. Remembering my sister Rosalind Franklin. The Lancet 2012, 379 (9821), 1094-1095.
14. Halton, B. Some unremembered chemists – Rosalind Elsie Franklin (1929-1958). Chemistry in New Zealand 2017, 81 (1), 38-45.
15. Doty, P. The DNA Story Part III, PLOS Biol 2004, 2 (3), e67, https://journals.plos.org/plosbiology/article ?id=10.1371/journal.pbio.0020067
16. Parry, D. Maurice Wilkins. New Zealand Geographer 2004, 067, https://www.nzgeo.com/stories/maurice-wilkins (accessed 11 June 2023)
17. An example is: Wasserman, M.; Liu, S. A tour de force on the double helix: Exploiting DNA mechanics To study DNA-based molecular machines. Biochemistry 2019, 58 (47), 4667-4676. doi: 10.1021/acs.biochem.9b00346.
18. An example is: Glenn, T.C.; Faircloth, B.C. Capturing Darwin's dream. Molecular Ecology Resources 2016, 19 (5), 1051-1058, doi: 10.1111/1755-0998.12574.
19. Zwart, H. The Third Man: Comparative analysis of a science autobiography and a cinema classic as windows into post-war life sciences research. History and Philosophy of the Life Sciences 2015, 37 (4), 382-412, doi: 10.1007/s40656-015-0080-z.
20. Anon. How Rosalind Franklin was let down by DNA’s dysfunctional team. Nature 2023, 616 (7958), 630, doi: 10.1038/d41586-023-01390-6; Anon. Rosalind Franklin was so much more than the 'wronged heroine' of DNA. Nature 2020, 583 (7817), 492, doi: 10.1038/d41586-020-02144-4.
21. Cobb, M.; Comfort, N. What Rosalind Franklin truly contributed to the discovery of DNA's structure. Nature 2023, 616 (7958), 657-660, doi: 10.1038/d41586-023-01313-5.
22. Cobb, M.; Comfort, N. What Watson and Crick really took from Franklin. Nature 2023, 616 (27 April 2023), 657-660.
23. Markel, H. The Secret of Life: Rosalind Franklin, James Watson, Francis Crick, and the Discovery of DNA’s Double Helix. Norton, 2021.
24. Derewenda, Z.S. A review of secret life: Rosalind Franklin, James Watson, Francis Crock and the discovery of DNA’s double helix by Howard Markel. Acta Crystallographica Section D 2022, 78 (12), 1409-1473.
25. An example is: Martin, L.; Neguembor, M.V.; Cosma, M.P. Women's contribution in understanding how topoisomerases, supercoiling, and transcription control genome organization. Frontiers of Molecular Biology 2023, 10 (March 27), doi: 10.3389/fmolb.2023.1155825.
26. Dai, P.; Williams, C.T.; Witucki, A.M.; Rudge, G.W. Rosalind Franklin and the discovery of the structure of DNA: Using historical narratives to help students understand nature of science. Science and Education 2021, 30, 659-692.
27. Park, P.; Leahey, E.; Funk, R.J. Papers and patents are becoming less disruptive over time. Nature 2023, 613, 138-144, https://doi.org/10.1038/s41586-022-05543-x .
28. Epitomized in science by so-called Kuhnian revolutions: Kuhn, T.S. The Structure of Scientific Revolutions. University of Chicago Press: Chicago, 1962.
29. Casadevall, A.; Fang, F.C. Editorial. American Society for Microbiology (mBio) 2016, 7 (2), e00158-16, https://journals.asm.org/doi/epub/10.1128/mBio.00158-16 (accessed 28 May 2023); Politi, V. Scientific revolutions, specialization and the discovery of the structure of DNA: toward a new picture of the development of the sciences. Synthese, 2018, 195 (5), 2267-2293 (accessed 28 May 2023)
30. For an example, see: Scerri, E.R. Evolutionary theories of scientific development. In A Tale of Seven Scientists and a New Philosophy of Science. Oxford University Press: New York, 2016, pp. 190-192.
31. Alkhteeb, F. Lost Islamic History: Reclaiming Muslim Civilization from the Past. Hurst: London, 2017, pp. 131-135.
32. Wilson, B. Metropolis: A History of the City, Mankind’s Greatest Invention. Vantage: United Kingdom, 2020, p. 131; Man, J. Saladin: The Life, the Legend and the Islamic Empire. Bantam: London, 2015, pp. 3-4.
33. Alkhteeb, F. op. cit., pp. 212-213.
34. Alkhteeb, F. op. cit., pp. 244-245.
35. Farman Farmaian, S. Daughter of Persia: A Woman’s Journey from Her Father’s Harem Through the Islamic Revolution. Corgi: London, 1992, pp. 452-453, 502.
36. Murphy Building, North end planter, https://www.wgtn.ac.nz/about/our-story/history/campus-plaques/campus-plaques.pdf (accessed 31 May 2023)
37. Maurice Wilkins Centre for Molecular Discovery, https://www.mauricewilkinscentre.org/about-us/what-we-do/ (accessed 31 May 2023)
38. Examples include: Morgan, P-J. Genomic medicine capabilities, in: World of Genomics – New Zealand, 26 July 2022, https://frontlinegenomics.com/world-of-genomics-new-zealand/ (accessed 1 June 2023); Next generation DNA, Institute for Environmental Science and Research (ESR), https://www.esr.cri.nz/our-research/our-science-in-action/next-generation-dna/ (accessed 1 June 2023); Genetics and epigenetics, at University of Otago, https://www.otago.ac.nz/dsm-pathology/research/otago117876.html (accessed 1 June 2023)
39. Thompson, C. Sea People, William Collins: Dublin, 2019, pp. 301-304; citing Skogland, P.  et al., Genomic insights into the peopling of the southwest Pacific. Nature 2016, 538 (October 27), 510-513; itself drawing on: Higham, T.; Anderson, A.; Jacomb, C. Dating the first New Zealanders: The chronology of Wairau Bar. Antiquity 1999, 73, 425-426.
40. Knapp, M.; Horsburgh, K.A.; Prost, S.; Matisoo-Smith, E.A. Complete mitochondrial DNA genome sequences from the first New Zealanders. PNAS 2012, 109 (45, October 3) 18350-18354. https://doi.org/10.1073/pnas.1209896109
41. Spriggs, M.; Howes, H. Archaeology as a profession in the Pacific (1945 – present). In: Howe, H.; Jones, T.; Spriggs, M. (eds) Uncovering Pacific Pasts: Histories of Archaeology in Oceania. Australian National University Press: Canberra, 2022, chapter26; Straiton, J. Ancient DNA sequencing: telling the tale of human history and evolution. Biotechniques 2023, 74 (1),  https://doi.org/10.2144/btn-2022-0121%20%20
42. Blust, R. The Austronesian homeland and dispersal, Annual Review of Linguistics 2019, 5, 417-434.
43. An example is: Chang, C-S.; Liu, H-L.; Moncada, X.; Chung, K-F. A holistic picture of Austronesian migrations revealed by phylogeography of Pacific paper mulberry. PNAS 2015, 112 (44), 13537-13542, https://doi.org/10.1073/pnas.1503205112
44. Blank, A. (compiler). Ora Nui 2021,4 New Zealand & Taiwan Special Edition, https://www.oranui.co.nz/shop/p/oranui-book (accessed 31 May 2023)
45. These sentiments are also stated in Wellington Central Library. Guide and Souvenir of Opening. 13^th February 1940, p. 7, https://wellington.recollect.co.nz/nodes/view/3433?keywords=central%20public%20library&type=all&highlights=WyJjZW50cmFsIiwicHVibGljIiwibGlicmFyeSJd&lsk=222460a0942a6b7d85a2f8a7591bb12d#idx4276 (accessed December 2022)
46. Rather than using local stone, Darley Dale sandstone (strictly ‘Stancliffe Darley Dale Stone’) was imported from England. Geologically this material is described as a “medium to coarse grained, hard, granular sandstone…. It comprises darker brown ferruginous specks, feldspar, and occasional flecks of mica”, https://archaeologydataservice.ac.uk/archives/view/stones_ahrb_2005/cfm/Public/details/RockDetails.cfm?RockCode=STANDD (accessed December 2022)
47. The new Library, layout of grounds, popular rendezvous. Evening Post 4 May 1939, p. 15.
48. The Rundel Memorial Building, Home to the Rochester Public Library, https://www.libraryweb.org/rochimag/architecture/SpecificBuildings/Rundel/Rundel.htm (accessed December 2022)
49. Hodder, C.; Hodder, P. Enclaves Above the City: A Brief History. HodderBalog: Wellington, 2022, pp. 75-102.
50. House and motor garage, opposite Victoria College. No. 30, Kelburn Parade. Evening Post 24 April 1929, p. 16.