A series that ends this week should inspire not only appreciation of images but also a desire to communicate.
lrresistibly and in occasionally peremptory fashion, science has, in recent years, embedded itself ever deeper into everyday culture.
One can reasonably assume that this infiltration will grow as science significantly extends and deepens our understanding of just what we are.
Visually, that cultural permeation can be witnessed at several lev- els. Citizens are surrounded by images, often taken out of scientific context, with values ranging from the ephemeral to the icon with an impact that resonates for decades. At a deeper level, scientific ideas and perspectives are absorbed by artists and significantly enrich their portrayals or creative extensions of the world.
For over a year, Martin Kemp has treated readers of Nature, week by week,to a seemingly endless celebration of diverse and often beautiful artistic and scientific images and the (respectively) scientif- ic and artistic impulses that can be traced within them. But the end has finally come (page 727). To judge by the author’selectronic mail- box, readers have been much stimulated. They will be pleased to know that he will continue to contribute regularly, albeit less fre- quently, in future. Meanwhile, researchers might consider the ever more important need to communicate their science not only to their peers but also in ways that others can appreciate and that artists in particular, occasionally but valuably, can creatively absorb.
World Bank backs Third World centres of excellence plan
A global chain of so-called Millennium Institutes, acting as scientific centres of excellence in developing countries to galvanize a rapid increase in their scientif- ic and technical strength, is being planned by the World Bank, private foundations and several governments.
The World Bank could grant the first loan, of around US$5 million, to establish proto- types for such institutes in Chile as early as next month, according to bank officials. The initiative has the strong personal support of Eduardo Frei, the president of Chile, and James Wolfensohn, the bank’spresident.
The institutes will be characterized by the fact that leading scientists from outside the host country will select their directors and review their performance, that the focus of research will be of direct relevance to that country’s economic and social needs, and that there will be frequent exchange of stu- dents and researchers with institutes abroad.
Frei has been discussing ideas for new sci- entific collaboration with other LatinAmeri- can leaders for more than a year (see Nature 391, 524–525; 1998). Wolfensohn, who is on the board of directors at the Institute for Advanced Study (IAS) at Princeton, New Jer- sey, and has been instrumental in focusing the bank on the ‘knowledge gap’ between industrialized and developing countries (see Nature 395, 529; 1998), badly wants to bolster science in the bank’s client countries.
Wolfensohn asked IAS director Philip Griffiths to investigate the possibility ofnew types of institutes to do this. Earlier this year Griffiths met Claudio Teitelboim, Frei’s science adviser. Their discussion led to the convergence of the two initiatives at a special meeting in June in Santiago, attended by scientific leaders from Latin America, the United States and Europe.
The meeting resulted in a concept for the Millennium Institutes which, supporters believe, will enable a small number of excel- lent researchers in developing countries to break free from the constraints on first-class international research there.
They believe this can be achieved by in- vesting a relatively small amount of money, directed at exceptional talent with guaran- teed long-term support and subject to review by leading scientists from other countries.
“We want to have a research group work- ing happily and feeling that they are not hindered by being in Chile rather than in Paris, New York or London,”says Teitelboim.
Teitelboim says Chile’s proposal is “a Chilean initiative that has the support ofthe World Bank” But bank officials and other advocates of the Millennium Institutes expect it to be rapidly followed by similar institutes elsewhere in Latin America, and that if successful, the concept will quickly spread to other regions of the world, includ- ing East Asia and Africa.
Bruce Alberts, the president of the US National Academy of Sciences, who attended the Santiago meeting, says that international peer review of the Millennium Institutes will
“keep out the politics that dominates science in developing countries”
He adds that the institutes will seek to transform the public image of science in these countries, where it is sometimes viewed as isolated from and subservient to economic and societal needs. “They’ll need to demon- strate value beyond just their academic value,” he says. “We want them to help bring science into the public consciousness ” The institutes will “be embedded in the university system” of their host countries, where their staff will be expected to teach.
Lauritz Holm-Nielsen, a senior science and technology specialist at the World Bank who runs the initiative there, says its rate of expansion will depend on the interest expressed by the bank’s client countries.
“We’re trying at first to work with Chile, Argentina, Brazil and Colombia,” he says.
Holm-Nielsen adds that the institutes will not adhere to any particular model or struc- ture, but will instead focus on supporting the best people, using “a variety of models” applicable to individual countries. The bank will expect host governments to adopt a poli- cy of long-term support for the institutes.
It will rapidly consider small “learning and innovation” loans, such as that requested by Chile,to start prototypes, and then larger loans for the long-term operation of the insti- tutes. One researcher familiar with the pro- gramme expects Chile to request $40–$60 million to operate its first batch of institutes.
Griffiths says several private foundations, including the Carnegie Corporation and the Fulbright programme, are involved in the discussions on the initiative or have already pledged grants to it. He hopes that around six prototype institutes will be established with- in a year.
For Chile, according to Teitelboim, “the key thing is to get the prototype to fly” He envisages “no more than three” prototype
Germany’s nuclear secrets can now be told [MUNICH] Formerly secret documents relating to Germany’s nuclear programme between 1938 and 1945 were transferred to Munich’s Deutsches Museum last week. The documents include research reports and
experimental protocols written by Germany’s Nobelprizewinners Werner
Heisenberg and Otto Hahn, as well as their correspondence with the government.
In 1938 Hahn, Lise Meitner and Fritz
Strassmann discovered the first evidence of the products of uranium nuclear fission.
After the beginning of the Second World War, the Nazis increased support for the nuclear research programme. The
documents show that until the early 1940s Germany and the United States were almost equally advanced in nuclear research.
Immediately after the war the Americans confiscated the documents, but theywere
returned to Germany in the 1970sand kept at the Karlsruhe National Research Centre.
The museum will make the documents freely available to historians. Quirin Schiermeier
institutes in Chile, together with “a larger number of nuclei”, where a single investigator will be supported, and which may later evolve into full institutes. A third element of funding will support visiting students and researchers. “There will be a very small number of perma- nent people, and a large flow of people visit- ing,” says Teitelboim.
The Chilean government will not decide the disciplines in which the institutes will specialize, nor their balance between pure and applied research. “To decide whether Chile should excel in this or that would defeat the purpose” of the initiative, Teitel- boim says. “We should scout for talent, and then follow that talent.”
The University of Salamanca in Spain is being taken to court by an astro- physicist who claims that a bias towards internal candidates denied him an associate professorship in its department of general and atmospheric physics.
A university panel has already rejected an appeal by the astrophysicist, Antonio Férriz Mas. It argues that, despite having better scientific qualifications than the individual appointed, his speciality of fluid dynamics was “significantly different” from the department’s requirements, namely atmos- pheric dynamics and thermodynamics
But Férriz Mas says the university has violated the principles of equality and meri- tocracy in assessing applicants for the post. University officials are not commenting publicly on the charges, which will probably take one to two years to reach court.
The administration of public universities in Spain has improved following reforms in 1983. But the selection process for profes- sors,known as the‘concurso-oposición’, is still widely seen as a considerable barrier to the development of high quality research.
A contract researcher already employed in a department is frequently given a tenured position,for example, even if they are not the most scientifically qualified applicant.
Under the 1983 law, appointment boards must have five members, at least three of whom must vote for the approved candidate. Two members come from the department concerned, and three from other universi- ties. But often the crucial third vote for a local
candidate is saidto be easily obtained.
Many concerned parties — including vice-chancellors and officials at the Ministry of Education and Culture — are now back- inga change in the law to give each university department only one vote, that of chair of the
appointment board (see below).
Férriz Mas worked at the University of Freiburg in Germany for three years as a PhD fellow and five as a postdoctoral researcher He returned to Spain in October 1994 under a programme spon- sored by the govern-
ment for ‘reincorpo- rating’ researchers. A month later he applied for a post in earth physics, astronomy and astrophysics at the University of Salaman- ca, and spent six months preparing the teaching project on atmospheric dynamics and thermodynamics. There were three candidates for the post.
In the first part of the examination, based on research experience and proposed teaching project, the examiners gave FérrizMas three points. The local candidate, who was put forward by the department and was eventu- ally awarded the post, received the top mark of five. The second exam, which involved giving a lecture, resulted in an equal score.
FérrizMas appealed against the decision. A year later, an appeal panel, chaired by vice- chancellor Ignacio Berdugo Gómez de la Torre, reported after taking advice from two foreign scientists. Both agreed that Férriz Mas’swork was “substantially more impor- tant” than that of the appointed candidate.
Despite this, Férriz Mas’s claim was rejected because the first part of the appoint- ment process depended on the match between the position’s ‘teaching profile’ and the research and teaching programme pro-
posed by the candidates. The appeal panel acknowledged that the appointment board “should have operated with a higher dili- gence, as the ‘fit’to the teaching profile must be clearly stated in preliminary information, as well as in the reports of the first exam”
The panel said it lacked the knowledge to judge how much the need to meet this‘teach- ing profile’ should take precedence over the quality of prior research and teaching.
The appointment process had already been questioned by the third candidate for the post, Fernando Atrio Barandela, associ- ate professor of theoretical physics at the
Atrio Barandela asked one member of the appointment board the reason for his score, and says he was told it was not intended to reflect the relative merits of the candidates, but rather the committee’spreferences.
A year later, FérrizMas applied for anoth- er post, an assistant professorship in the theo- retical physics group, with an astrophysics teaching profile, at the university’sFaculty of Sciences. The post involved instruction in using telescopes, but was given to a chemist.
Again FérrizMas appealed. This time the appeal panel, again chaired by Gómez dela Torre, accepted that the person appointed had a worse fit to the teaching profile than Férriz Mas — but had substantially better research and teaching experience.
Férriz Mas says that this second decision confirms that the local candidate was the predetermined choice for each post, and that there is often an unspoken agreement among the members of appointment boards.
In such cases, he argues, the deciding third voice seals a pact where board members return the favour in the future. He says that committee members have total impunity.
Many Spanish researchers are critical of the process. Benjamin Montesinos, director of the laboratory of space astrophysics and
fundamental physics, an ‘associated unit’ of the Institute of Astrophysics of Andalusia (Higher Council of Scientific Research), says that a smokescreen of complex arguments is often used to justify appointing an internal candidate to a post.
He argues that examiners who assess applicants to jobs in universities should have nolink with the department concerned.
Luis F. Rull, professor of physics at the University of Seville, says the argument used against FérrizMas — that fluid dynamics is a different discipline to atmospheric dynamics and thermodynamics — is false. Rull calls for common standards and wants a public rank- ing of disciplines, perhaps based on publica- tion record, impact factor and citations.
Juan J. Manfredi, professor of mathemat- ics at the University of Pittsburgh, says that many qualifications are used by appoint- ment boards to disqualify candidates who maybe better than local candidates.
He says that some positions define a teaching profile (instead of area of knowl- edge) so closely that only one candidate can meet the criteria. This process, he argues, goes directly against the cross-fertilization that research requires
Europe bids for molecular biology ‘club’
The European Molecular Biology Organization (EMBO), which promotes molecular biology through fellowships, conferences and workshops, is to launch a series of young investigator awards.
EMBO hopes that the five-year awards will be sufficiently prestigious to encourage the brightest young scientists to install themselves permanently in laboratories across Europe. Those eligible must be within eight years of completing their PhD.
The intention is that EMBO Research Sci- entists, as the recipients of the awards will be called, will form a ‘club’ of top-level molecu- lar biologists who will maintain links with each other and with research group leaders at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany, for at least the duration of the fellowships.
The governments of EMBO’s 23 member states, which operate collectively as the European Molecular Biology Conference, last week agreed in principle to finance the scheme. If all goes smoothly, they will decide on its permanent level of financing in 2000. EMBO is expected to launch the scheme by contributing ECU500,000 (US$590,000)
of its current budget annually into a pool of funds, which is expected to be expanded by donations from other sources such as chari- ties and foundations. Some member coun- tries will also be expected to contribute to this pool, the largest contributions coming from the richer countries.
EMBO Research Scientists will be given a salary, the costs of running a small laborato- ry conducting research independent of the host institute’s tenured scientists, and travel expenses associated with ‘networking’ — attending an annual meeting and visiting other laboratories in the‘club’
Some candidates would already be receiving national young investigator awards. They would receive no support from EMBO for salaries and laboratory costs, but would receive full support for networking.
Any member state wishing to increase its number of EMBO Research Scientists in this
category could do so by making a further payment. This could be used to top up the resources of all the EMBO Research Scien- tists in that country if the national young investigator award is judged to be signifi- cantly lower than the European average.A second category would be selected in the first instance by EMBO. The relevant member state would agree the choice ofcan didate and pay a significant proportion of salary and running costs. The remainder would come from the EMBO awards pool.
“EMBO’s selection committee will ensure the high standard of selected Research Scientists, and ensure that their quality is uniform throughout Europe,” says Frank Gannon, director of EMBO. “I expect the initiative will become an important com- ponent of scientific life in Europe, one which identifies high-quality researchers at anearly stage in their careers, and helps us to keep such individuals in Europe ” Maria Carmo Fonseca, a professor of cell and molecular biology at the University of Lisbon, who previously worked at EMBL, says the strong networking component will be particularly helpful in attracting back to
“peripheral” countries, such as Portugal and Spain,young scientists who trained abroad.
The Portuguese Ministry of Research has already agreed to setup a young investigator award scheme that will allow it to exploit the EMBO scheme, she says.
South Korean researchers under fire for claims of human cloning
[TOKYO] A South Korean research team, which announced last week that it had cloned a human embryo, has been criticized by other researchers for refusing to disclose the evidence to backup its claim.
Indeed, many doubt whether the cloning experiment, claimed to be the first to have produced an embryo from a human somatic cell,has produced promising results.
Researchers from Kyunghee University Hospital in Seoul announced at a press conference that they had cultivated an earlystage embryo using an unfertilized egg and a somatic cell from a female patient who had been receiving infertility treatment there.
The team, led by Kim Seoung Bo and Lee Po Yon, professor and associate professor in obstetrics and gynaecology at Kyunghee
University, injected nuclei from granulosa cells (differentiated cells that surround the oocyte) into enucleatedoocytes.
Of six fertilized eggs, one divided to the four-cell stage. Researchers say they then
destroyed this ‘embryo’ without implanting it into a human body. They say they adapted the technique used by researchers from the University of Hawaii, who have cloned
several generations of mice using granulosa cells (see Nature 394, 369–373; 1998).
“The experiment was carried out purely for the purpose of medical research, and not for clinical purposes. The fertilized egg was not implanted in the uterus of the donor, as we have no intention of creating a cloned baby,” said Lee at the press conference.
Lee says the experiment was conducted according to ethical rules on artificial
fertilization laid down by the South Korean Medical Association in 1993,which prohibit the implantation of genetically engineered human embryos. The government is
compiling a draft bill on the regulation of human cloning research, which is expected to pass the congress early next year.
Although the research team has no plans for any further experiments until the new legislation is ready, it hopes to use the
technique to develop cells and tissues for replacement therapy and to treat infertility.But there is widespread concern among the public, even though the experiment stopped short of producing a full human clone. The Korean Federation for the Environment Movement, for example, says human cloning research, if misused, could result in a “great mishap to all mankind” There was a more muted response from the scientific community in South Korea, with some doubting its success, as no evidence has been released.
“The lack of a scientific presentation leads us to think that their results are not ‘hair raising’ in terms of a scientific breakthrough,” says Dae-Young Uhm,associate professor in physiology at
Sungkyunkwan University. “The only notable social response was from the civil rights groups ”
Kim refuses to release evidence of the experiment’s success to avoid further controversy. “We have strong evidence, including photos, but we will not release it now as we believe our reputation has been damaged enough,” he says. Making a case in the corridors of power
Britain’s corridors of power last week witnessed a rather unusual gathering of scientists and senior ministers who — in the company of some potted plants — assembled in 10 Downing Street to brief the primeminister, Tony Blair, on why science matters, the issues surrounding public investment in science and its policy implications.
The presentations were made in a series of tightly orchestrated, four-minute slots, delivered around the long, boat-shaped Cabinet table. The potted plants,reputedly the first to be placed squarely on the
Cabinet table in front of the primeminister, arrived with Caroline Dean from the John Innes Centre in Norwich, who talked about her work on the genes in the plant Arabidopsis. Dean was among those whose talk came under the heading, “A Taste of Science” . Any resonance with the billing found on the back of pre-prepared supermarket
meals — “A Taste of India” — was a reminder that for most government ministers, science might as well be a far-flung foreign land. But the scientists present left the meeting rather pleased. “I felt that science had moved to the top of the agenda,” says Paul Nurse,director-general of the Imperial Cancer Research Fund.“I’m prepared to be as cynical as the next person, but I came away feeling fairly impressed and upbeat about the whole thing,” says
Matthew Freeman of the Medical Research Council’s Laboratory of Molecular Biology in Cambridge.
According to the reports of those present, ministers talked of the recent success of the Research Assessment Exercise conducted on British universities, and there was cautious discussion of a possible new white paper on science.It also appeared clear that senior ministers were not confident that the recent
announcement of significant additional funds for science (see Nature 394, 209; 1998) was likely to be sufficient to silence scientists, and they were expecting further calls for money.
The scientists in turn delivered some important messages about the difficulties of finding adequate funding for their work. One of those present was Polina Bayvel of University College London, representing the country’s electrical
engineering departments.
Already backed by a prestigious Royal Society University Research Fellowship, Bayvel has raised £1.5 million (US$2.5 million) for an optical communications laboratory — but the effort has involved writing more than 35 grant proposals over the past five years. The need for long-term funding for good scientists was driven home by Matthew Freeman, who used his own highly successful laboratory as an example.
Despite being billed as a mix of young and old, and life and physical scientists, the meeting inevitably ruffled a
few feathers. “The make-up of the meeting clearly reflected a life-sciences bias,” said one physicist. “This is
understandable, but what’s worrying is there might be an ideology to fund life sciences more because they create
more wealth.” For many, however, the surprise turn of the meeting was the widely distrusted trade and industry secretary Peter Mandelson, who, despite his reputation as the Labour party’s ‘spin-doctor’, seems to have made
something of a hit with the assembled academics. “I really liked Mandelson,” said one. “I hadn’t expected to, as his image is an alarming one. [But] he was intelligent and
had a really sharp, black sense of humour.” Towards the end came
discussion of how to improve science’s poor public image. National Science Week,
suggested one participant, needed some high-profile events — such as a minister bungee jumping off a tall
building to demonstrate Newtonian dynamics and Hooke’s law.
“Haven’t you heard?”
quipped Mandelson. “I’m
doing that from the
Millennium Dome” . Such an
event would certainly serve
to attract visitors to the
government’s £758-million
dome, which houses an
exhibition celebrating the
millennium.
Britain embrace ‘knowledgey economy’
The British government has pledged to put the commercialization of sci- entific knowledge at the heart of its industrial policy. The move comes in an ambitious and wide-r ing series of initiatives announced
last week, including a white paper on how sci- ence can enhance economic competitiveness.
But implementing the initiatives is likely to be controversial. Some ministers in the Labour government are concerned that some proposals clash with the priorities of other government departments.
The white paper (policy document) includes a new £150 million (US$252 mil- lion) national venture capital fund to help finance small businesses with the potential to grow, such as high-technology companies. It also includes a £20 million annual Higher Education Reach Out fund to reward univer- sities in England that work with businesses.
Universities in Scotland will receive £34 mil- lion over three years. Existing schemes encouraging academics to work with industry are also being expand- ed while £75 million for equipment is being
given under the Joint Research Equipment Initiative (see Nature 396, 607; 1998).
Some of the thinking behind the white paper is borrowed from the United States. For example, the science minister, Lord David Sainsbury, is to coordinate a series ofstudies into the extent to which high-technology companies in Britain can benefit by being located in clusters such as those to be found in Silicon Valley or around Boston.
The white paper includes a government- sponsored review of whether publicly funded research establishments are making the best use of intellectual property rights to maxi-
mize the commercial returns from research.
Launching the initiatives, Peter Mandel- son, Secretary of State for Trade and Industry, said that,as a high-wage economy with high land and transport costs and few raw materi- als, the United Kingdom’s best hope of raising economic growth rates is by exploiting the potential of‘knowledge industries’
Many see the white paper as a significant step in the Labour party’s shift away from its traditional socialist roots to its present posi- tion as a party of the centre-left, comfortable both with increased public investment and free markets. This is a shift that Mandelson personally helped to engineer, and he has strong backing from Sainsbury.
In a newspaper article published the day after the white paper’s launch, Mandelson wrote that he was a politician “confident that his white paper marks a turning point in ide- ology and policy for his party and his coun- try” The message was plain, he wrote: “Labour has dumped its interventionist past ”
This language, and the emphasis on rely- ingon science to create wealth,concerns min- isters with more traditional socialist leanings. These include Michael Meacher, the environ- ment minister, and his boss, John Prescott, the deputy primeminister.
Mandelson and Sainsbury will face one of their first tests over the development of high- technology clusters. These businesses are likely to be subjected to rigorous and lengthy planning applications, particularly if they are to be built in or near rural areas.
Mandelson says he wants planning appli- cations from high-technology industries to be dealt with such that “the national econom- ic interest is taken into consideration” But the environment department, which oversees the planning system, is anxious that environ- mental considerations should not be down- graded, according to officials.
A key test of this is likely to bean applica- tion by the Welcome Trust to build a science park next to its genetics research centre at Hinxton Hall near Cambridge. The planning inspector has rejected the proposal. But this decision has yet to be endorsed by Prescott.
Another battle looms over biotechnology regulation. The environment department plans to include more public representatives on its committee of scientists that advises the government on the safety of proposed geneti- cally modified crops.
It also wants applications to grow such crops to be seen by an additional ethics com- mittee. But the Department of Trade and Industry (DTI) is likely to oppose this on behalf of industry, which fears that further regulations will be time-consuming and a threat to economic competitiveness.
This battle will be fought out in a forth- coming review of the structure of Britain’s biotechnology regulatory system, also announced last week. The review, to be car- ried out by the Cabinet Office and the Office of Science and Technology, will include pub- lic consultation on the regulatory process.
It has been setup partly in response to the collapse in public confidence in government science advice during the crisis over bovine spongiform encephalopathy, and partly to address public concern that regulations on the planting of genetically modified crops do not adequately address safety issues.
One senior environment civil servant says the spectre of a possible recession is one rea- son that the DTI is keen to help setup knowl- edge-based companies. But she says her department will face severe public criticism if environmental and safety considerations are relaxed.
Longevity and the barren aristocrat
Experiments with fruitflies have shown that those with fewer offspring generally live longer. Twelve-hundred years of genealogical data from British aristocrats now suggests that this relationship extends to humans.
when Madame Jeanne Calment (Fig.1) died last year, at a record-breaking 122 years of age, gerontologists debated just what accounted for her extraor- dinary longevity. According to a report by Westendorp and Kirkwood1 on page 743 of this issue, at least part of Madame Calment’s Methuselean lifespan may have been due to her having had only one child. These authors used data from genealogies of the British aristocracy to show that lifespan is negatively correlated with family size — a result that supports predictions from evolutionary models of ageing.
Ageing is an inevitable result of the declining force of natural selection with age2. For example,a mutant gene that halves the survival rate among young children will be strongly selected against. But a gene of simi- lar magnitude whose effects are confined to people over the age of 90 will experience no selection because people with this deleteri- ous gene will have passed it to their offspring long before its effects become apparent. So, over evolutionary time, late-acting delet-
erious genes will accumulate, leading to an increase in mortality rates late in life. Indeed, late-acting deleterious genes may even be favoured by selection if they have beneficial effects early in life — agenetic mechanism dubbed ‘antagonistic pleiotropy’3 . This trade-off between benefits at anearly age and
costs later was explained by Kirkwood over 20 years ago in his ‘disposable soma’theory4, which predicts that any investment in re- production diverts resources away from the maintenance and repair of cells, with ageing as a result (Fig. 2).
The antagonistic-pleiotropy and dispos- able-soma theories both indicate that those who invest heavily in reproduction while young will pay for this reproductive success with ashortened lifespan. Researchers have
found support for this prediction in many model organisms. In the fruitfly Drosophila melanogaster, for example, flies selected for long lifespan have reduced early fecundity5.
Now, thanks to the extensive genealogical records that have been kept on the British
aristocracy for the past 1,200 years, Westen- dorp and Kirkwood1 have identified the predicted trade-off in humans. The authors obtained records for 19,830 male and 13,667 female aristocrats born between 740 and 1875, then looked at the dates of birth and death, number of children, and the age at which each child was born. For women who survived to at least 60 years of age, they found a negative correlation between the number of years survived beyond 60 and the number of children. (The pattern among men was virtually identical.) Similarly, women who started reproducing later (and, presumably, had smaller families) lived longer. Almost half the women who surpassed 81 years of age had no children, yet fewer than one-third of the women that died before that age were childless.
One might argue that the negative corre- lation between family size and longevity is due to changing demographic trends — starting around 1700, average family size decreased and longevity increased among the British aristocracy. To ensure that this demographic transition was not the under- lying cause of the negative correlation between longevity and the number of chil- dren, the authors analysed cohorts born before 1700 and after this time separately. In both cases, the correlation between lifespan and number of progeny was negative, although evidence for the trade-off was much greater among women born before 1700 than those born more recently.
This study, and previous tests of evolu- tionary theories for ageing using human data6,7, assumes that the observed variation in longevity is due, at least in part, to genet- ics. Westendorp and Kirkwood show that longevity is correlated between parents and
offspring, suggesting a heritable basis to ageing. However, for genealogical studies at least, we cannot distinguish the effects of genetic similarity from those of common environment. The authors find that longevi- ty is correlated not only between parents and offspring, but also between husband and wife. So, inbreeding aside, it is fair to assume that any correlation of longevity between spouses is due to a shared environment, not shared genes.
Westendorp and Kirkwood reduce potential environmental variation by limit- ing their study to the aristocracy. But even among this relatively homogenous class one might expect substantial variation in wealth and general environment — not only across the centuries, but even among families living in the same period. The new results are powerful evidence for a correlation between
reproduction and longevity in British aristo- crats. In the search for trade-offs, however, correlation does not prove causation8, and it remains to be seen whether the observed patterns are due to nature or nurture.
Nevertheless, Westendorp and Kirk- Can we conclude that having fewer chil- dren extends life expectancy? Although childless women benefit from a decreased incidence of heart disease and cervical cancer later in life, they have an increased risk of breast cancer and respiratory disease10.
an ocean comprised almost completely of such water, which would have a dramatic effect on the climate.
This doesn’t happen, because the deep ocean is stirred. But how? In “Abyssal recipes” Munk sought a balance between thewood’s results raise intriguing questions that Clearly, many factors influence lifespan, and upwelling of cold water with mixing down might be addressed with this extraordinary readers can rest assured that having more
human database. First, for half a century, evo- children will not necessarily send you to an
lutionary biologists studying life-history early grave. After all, Queen Victoria gave
strategies have been interested in the evolu- birth to nine offspring, all of whom survived,
tion of clutch size (number of progeny)9. The and lived to be 81 years old — in her day, a
database can now be used to determine ripe old age.
Comments
Post a Comment