Saturday, 7 December 2013

ancient humans

Saturday, 7 December 2013

Neanderthal sex boosted immunity in modern humans

Labels: evolve

Neanderthal sex boosted immunity in modern humans

By Matt McGrathScience reporter, BBC World Service Infographic

Human leucocyte antigen (mauve) is expressed on the outside of white blood cells

Sexual relations between ancient humans and their evolutionary cousins are critical for our modern immune systems,researchers report in Science journal.

Mating with Neanderthals and another ancient group called Denisovans introduced genes that help us cope with viruses to this day, they conclude.

Previous research had indicated that prehistoric interbreeding led to up to 4% of the modern human genome.

The new work identifies stretches of DNA derived from our distant relatives.

In the human immune system, the HLA (human leucocyte antigen) family of genes plays an important role in defending against foreign invaders such as viruses.

The authors say that the origins of some HLA class 1 genes are proof that our ancient relatives interbred with Neanderthals and Denisovans for a period.

“Start Quote

Getting these genes by mating would have given an advantage to populations that acquired them”

Peter Parham

At least one variety of HLA gene occurs frequently in present day populations from West Asia, but is rare in Africans.

The researchers say that is because after ancient humans left Africa some 65,000 years ago, they started breeding with their more primitive relations in Europe, while those who stayed in Africa did not.

"The HLA genes that the Neanderthals and Denisovans had, had been adapted to life in Europe and Asia for several hundred thousand years, whereas the recent migrants from Africa wouldn't have had these genes," said study leader Peter Parham from Stanford University School of Medicine in California.

"So getting these genes by mating would have given an advantage to populations that acquired them." Meet the Denisovans

When the team looked at a variant of HLA called HLA-B*73 found in modern humans, they found evidence that it came from cross-breeding with Denisovans.

Scanty remains

While Neanderthal remains have been found in many sites across Europe and Asia, Denisovans are known from only a finger and a tooth unearthed at a single site in Russia, though genetic evidence suggests they ranged further afield.

"Our analysis is all done from one individual, and what's remarkable is how informative that has been and how our data looking at these selected genes is very consistent and complementary with the whole genome-wide analysis that was previously published," said Professor Parham.

A similar scenario was found with HLA gene types in the Neanderthal genome.

"We are finding frequencies in Asia and Europe that are far greater than the whole genome estimates of archaic DNA in modern humans, which is 1-6%," said Professor Parham.

The scientists estimate that Europeans owe more than half their variants of one class of HLA gene to interbreeding with Neanderthals and Denisovans.

Asians owe up to 80%, and Papua New Guineans up to 95%.

Uneven exchange

Other scientists, while agreeing that humans and other ancients interbred, are less certain about the evidence of impacts on our immune system.

"I'm cautious about the conclusions because the HLA system is so variable in living people," commented John Hawks, assistant professor of anthropology at the University of Wisconsin-Madison, US.

DNA from a tooth (pictured) and a finger bone show the Denisovans were a distinct group

"It is difficult to align ancient genes in this part of the genome.

"Also, we don't know what the value of these genes really was, although we can hypothesise that they are related to the disease environment in some way."

While the genes we received might be helping us stay a step ahead of viruses to this day, the Neanderthals did not do so well out of their encounters with modern human ancestors, disappearing completely some 30,000 years ago.

Peter Parham suggested a parallel could be drawn between the events of this period and the European conquest of the Americas.

"Initially you have small bands of Europeans exploring, having a difficult time and making friends with the natives; but as they establish themselves, they become less friendly and more likely to take over their resources and eliminate them.

"Modern experiences reflect the past, and vice versa."

DNA: the 'smartest' molecule in existence

DNA: the 'smartest' molecule in existence?

By Jennifer Green and Dhruti ShahBBC Science

Composite image of zip, ladder, DNA strand, Morse code (courtesy Porthcurno Telegraph Museum) and telephone coil. Other images via Getty

DNA is structured like a ladder, opens and closes like a zip, codes data like Morse code and coils tightly

DNA is the molecule that contains and passes on our genetic information. The publication of its structure on the 25th of April 1953 was vital to understanding how it achieves this task with such startling efficiency.

In fact, it's hard to think of another molecule that performs so many intelligent functions so effortlessly. So what is it that makes DNA so smart?

Multi-millennial survivor

For such a huge molecule, DNA is very stable so if it's kept in cold, dry and dark conditions, it can last for a very, very long time. This is why we have been able to extract and analyse DNA taken from species that have been extinct for thousands of years.

Scientists have 'resurrected' blood protein from preserved mammoths after harvesting their DNA

It's the double-stranded, double-helix structure of DNA that stops it falling apart.

DNA's structure is a bit like a twisted ladder. The twisted 'rails' are made of sugar-phosphate, which give DNA its shape and protect the information carrying 'rungs' inside. Each sugar-phosphate unit is joined to the next by a tough covalent bond, which needs a lot of energy to break.

In between the 'rails', weaker hydrogen bonds link the two halves of the rungs together. Individually each hydrogen bond is weak - but there are thousands of hydrogen bonds within a single DNA molecule, so the combined effect is an extremely powerful stabilising force.

It's this collective strength of DNA that has allowed biologists to study genes of ancient species like the woolly mammoth - extinct but preserved in the permafrost.

This short animation explains everything else you need to know about DNA.

Clever facsimile machine

Our cells need to divide so we can grow and re-build, but every cell needs to have the instructions to know 'how to be' a cell.

Intelligent error correction

The consequences of wrongly read or copied information can be disastrous and cause deformities in the proteins.

So as DNA replicates, enzymes carry out a proof-reading job and fix any rare errors.

They tend to repair about 99% of these types of errors, with further checks taking place later.

Can the Human Genome project help spot common genetic mutations?

DNA provides those instructions - so a new copy of itself must be made before a cell divides.

It's the super-smart structure that makes this easy. The 'rungs' of the DNA ladder are made from one of four nitrogen-based molecules, commonly known as A, T, G and C. These form complementary pairs - A always joins with T and G always joins with C.

So one side of the double-stranded DNA helix can be used as a template to produce a new side that perfectly complements it. A bit like making a new coat zip, but by using half of the old zip as a template.

The original side and the new one combine together to form a new DNA double helix, which is identical to the original.

Cleverly, human DNA can unzip and 'replicate' at hundreds of places along the structure at the same time - speeding up the process for a very long molecule.

Molecular contortionist

Two metres of DNA coils like a telephone cord to fit into each cell

DNA is one of the longest molecules in the natural world. You possess enough DNA, stretched out in a line, to reach from here to the sun and back more than 300 times.

Yet each cell nucleus must contain two metres of DNA, so it has to be very flexible. It coils - much like a telephone cord - into tight complex structures called chromatins without corrupting the vital information within.

DNA bases - vital rungs in the ladder

There are four different nucleotide bases in each DNA molecule:

Adenine (A)
Thymine (T)
Guanine (G)
Cytosine (C)

These small molecules join DNA together and encode our genetic information.

And despite being packed in so tightly, the genetic material can still be accessed to create new copies and proteins as required.

Human cells contain 23 pairs of chromosomes, with each containing one long DNA molecule as well as the proteins which package it. It's no wonder DNA needs to be extremely supple.

Amazingly, this folded and packed form of DNA is approximately 10,000 times shorter than the linear DNA strand would be if it was pulled taut.

This is why we have the 'luxury' of having the plans for our entire body in nearly every cell.

Biological database

DNA storage

A research team has encoded data in artificially produced segments of DNA, including:

A 26-second snippet of Martin Luther King's classic anti-racism address from 1963
A .pdf" of the seminal 1953 paper by Crick and Watson describing DNA' structure

The total data package was equivalent to 760 kilobytes on a computer drive. Physically, the DNA carrying all that information is no bigger than a speck of dust.

Genes are made up of stretches of the DNA molecule which contain information about how to build proteins - the building blocks of life which make up everything about us.

Different sequences of the four types of DNA bases make 'codes' which can be translated into the components of proteins, called amino acids. These amino acids, in different combinations can produce at least 20,000 different proteins in the human body.

Think of it like Morse Code. It too uses only four symbols (dot, dash, short spaces and long spaces), but it's possible to spell out entire encyclopaedias with that simple code.

Just one gram of DNA can hold about two petabytes of data - the equivalent of about three million CDs.

That's pretty smart, especially when you compare it to other information-storing molecules. Using the same amount of space, DNA can store 140,000 times more data than iron (III) oxide molecules, which stores information on computer hard drives.

DNA may be tiny but with properties including stability, flexibility, replication and the ability to store vast amounts of data, there's a reason why it must be one of the smartest known molecules.

With huge quantities of data being produced by ever-growing computer systems, traditional data storage solutions, like magnetic hard drives are becoming bulky and cumbersome. Researchers have now used DNA to store artificially-produced information, but could this be the future of data storage?

Find out how all DNA's qualities could lead to extinct animals being resurrected

Tuesday, 3 December 2013

male and female brains different

Most autism research involves boys and men

Autism affects male and female brains differently, a study has suggested.

UK experts studied brain scans of 120 men and women, with half of those studied having autism.

The differences found in the research, published in journal Brain, show more work is needed to understand how autism affects girls, the scientists say.

Experts said girls with the condition could be more stigmatised than boys - and it could be harder for them to be diagnosed at all.

Autism affects 1% of the population and is more prevalent in boys, so most research has focused on them.

In this study, scientists from the Autism Research Centre at the University of Cambridge used magnetic resonance imaging (MRI) to examine how autism affects the brain of males and females.

Male and female brains differ anyway - tissue volume is greater in males.

'Look-alikes'

The study looked at the difference between the brains of typical males and those with autism - and then females with and without autism.

“Start Quote

There really needs to be more research and clinical attention toward females 'on the spectrum'”

Dr Meng-Chuan LaiUniversity of Cambridge

They found the brains of females with autism "look" more like - but still not the same as - typical male brains, when compared with the brains of females without autism.

But the same kind of difference was not seen in males with autism - so their brains did not show "extreme" male characteristics.

Dr Meng-Chuan Lai, who worked on the study said: "What we have known about autism to date is mainly male-biased.

"This research shows that it is possible that the effect of autism manifests differently according to one's gender.

"Therefore we should not blindly assume that everything found for males or from male-predominant mixed samples will apply to females."

He said future research may need to look at males and females equally to discover both similarities and differences.

Dr Lai added: "Lastly, there really needs to be more research and clinical attention toward females 'on the spectrum'."

'Masking'

“Start Quote

Many girls go on to develop secondary problems such as anxiety, eating disorders or depression”

Carol Povey,National Austitic Society

Carol Povey, Director of The National Autistic Society's Centre for Autism, said: "Historically, research on autism has been largely informed by the experiences of men and boys with the condition.

"This important study will therefore help our understanding of how the condition differs between genders."

She added: "Girls can be more adaptive than boys and can develop strategies that often mask what we traditionally think of as the signs of autism.

"This "masking" can lead to a great deal of stress, and many girls go on to develop secondary problems such as anxiety, eating disorders or depression.

"It's important that we build on this study and more research is conducted into the way autism manifests in girls and women, so that we can ensure that gender does not remain a barrier to diagnosis and getting the right support."

Friday, 15 November 2013

A new contract for GPs will see the return of "proper family doctors

A new contract for GPs will see the return of "proper family doctors," responsible for round-the-clock care and with dedicated help for the elderly, the Health Secretary says
The deal agreed with the British Medical Association (BMA) has been heralded as the biggest shake-up since Labour introduced changes which allowed thousands of doctors to abandon responsibilty for out-of-hours care.
Under the contract four million elderly patients and those with complex conditions will be given a named GP, personally accountable for their care at all times.
Ministers say the change is crucial because the failure to care for older patients has causing a spiralling crisis in NHS emergency care, with millions of patients admitted to hospital because they could not get help in time from their GPs.
Under a deal introduced by Labour, the majority of family doctors dropped responsibility for out-nstantly by almost one third.
BMA negotiators later admitted the terms, which brought average GP incomes to more than £100,000 were so generous that they thought the Government was "having a laugh".
Since then, there have been a succession of scandals in which patients were failed by locum doctors, including a notorious case when a pensioner was killed by an overdose of painkillers administered by an overseas medic working his first shift.
The new deal will mean that GPs are personally responsible for the care of all patients aged 75 and over, around the clock, regardless of who delivers it - as well as for the care for younger patients with complex health needs.
Older patients will also be promised same-day access to their doctors, via telephone consultations, while GPs will be instructed to draw up "personalised care plans" so all frail and elderly patients are properly looked after.
Jeremy Hunt said last night: "Labour's 2004 GP contract broke the personal link between GP and patient. It piled target after target on doctors, took away their responsibility for out-of-hours care and put huge pressure on our A&E departments. This Government has a plan to sort this out. Today's announcement of a new GP contract is a vital step."
Ofsted-style ratings measuring the performance of GP practices as outstanding, good, requires improvement or inadequate, will be published in every surgery by 2015, while data will be published scrutinising the quality of out-of-hours care for all patients.
Government sources said the reports would be detailed and "unapologetically frank" informed by close observation and conversations with professionals and patients.
Mr Hunt said: "We are bringing back named GPs for the vulnerable elderly. This means proper family doctors, able to focus on giving elderly people the care they need and prevent unnecessary trips to hospital. This is about fixing the long-term pressures on our A&E services, and freeing hardworking doctors to improve care for those with the greatest need."
Since 2004, GPs pay has been dictated by hundreds of targets. Under the system - derided by critics as "points mean prizes" - income can be dictated by how many patients are weighed, asked about their alcohol intake or given lifestyle advice.
Under the new deal, which will be introduced in April, more than one third of the indicators will be scrapped, which the BMA said would allow thousands of GPs to attend to their patients, instead of their computer screens.
Dr Chaand Nagpaul, Chairman of the BMA's GP committee, said: "This is resurrecting what used to happen: it means tailored and personalised care."
"The 2004 contract brought unprecedented bureaucracy and chasing of targets and box-ticking. We have removed a swathe of targets: what this is doing is giving GPs time - time to care. Doctors will be able to look at the patient in front of them, not the computer screen."
Under the targets framework, doctors have been paid for improving their handwriting, or ensuring staff undergo training, or for asking patients how often they do activities such as DIY, cooking or gardening.
Dr Nagpaul said: "Even today GPs up and down the land are asking these questions - how often patients cycle, garden or cook, how often they walk - and how quickly - checking the blood pressure of fit and healthy people, all the while measuring rather than providing care."
The deal agreed yesterday involves some compromises, as ministers had orginally indicated that they wanted GPs to take back responsibilty for out-of-hours care for all patients, and further changes are likely to be negotiated in future years.
Dr Nagpaul said: "Given the workforce crisis among GPs it's right to focus on the patients with the greatest need. I think the Government understsands that with a limited workforce GPs need to use their time wisely."
The BMA said the terms would not increase funding for doctors - who on average earns £103,000, with more than 600 earning more than £200,000 - but would shift existing resources, so GPs could make better use of their professional judgement.
Andy Burnham , Labour's Shadow Health Secretary, said: "No amount of spin can hide the fact that David Cameron has made it harder to get a GP appointment. There is nothing in this new contract to correct that."
"David Cameron cut Labour's scheme of evening and weekend opening and the guarantee of seeing a doctor within 48 hours. "This announcement will not put an end to patients phoning the surgery at 9am and finding it impossible to get an appointment - many of whom, not happy with a phone consultation, will still turn to A&E."

GPs take on extra role for frailest patients

By Nick TriggleHealth correspondent, BBC News

Jeremy Hunt said he hoped this would be part of a "much bigger change"

The 100,000 most frail patients in England will be identified and given a named GP to co-ordinate their care.

The move has been agreed by the British Medical Association and NHS England in talks over next year's GP contract.

Ministers had been pushing for doctors to take greater responsibility for the most vulnerable patients in society to relieve pressure on hospitals.

An analysis by NHS England showed many of the winter pressures on A&E came from frail elderly patients.

Contrary to common perception, it found that summer was the busiest time for A&E units in terms of numbers, but winter was when the difficulties arose because of the rise in the numbers of elderly patients needing care.

A third of emergency admissions are among the over-75s - many of which could be avoided if they received earlier and better care in the community.

This is where the agreement with GPs - which will kick in next April - will help, ministers say.

'Old-fashioned' approach

Under the terms of the deal, doctors have agreed to carry out a trawl of their registers to identify the frailest 2% of patients.

Dr Richard Vautrey from the BMA: "This will mean GPs will spend less time focusing on box ticking... and more time on the needs of their patients"

This is likely to include people at the end of life, in care homes and those who are frequently in and out of hospital.

They will then take responsibility for overseeing their care across the NHS and social care sectors.

“Start Quote

This will free up GPs to spend more time focusing on treating patients”

Dr Chaand NagpaulBritish Medical Associaton

The aim is to create a much more proactive services whereby their needs - from home adaptations to intensive nursing support - are met much more quickly.

They will also need to offer these patients same-day telephone consultations as well as checking up on them after discharge from hospital.

This contrasts with what the government and doctors' leaders agree is the more reactive service many patients are currently getting.

A further four million people over the age of 75 will be given a named GP - at the moment patients are registered to a practice rather than individual doctor. It is hoped this will lead to greater continuity of care for those patients who visit GPs the most.

'Phone frustration'

Health Secretary Jeremy Hunt hailed as the return of the "old-fashioned family doctor" and an end to the current "box-ticking" culture.

"We are bringing back the named GPs for the vulnerable elderly. This means proper family doctors able to focus on giving elderly people the care they need and prevent unnecessary trips to hospital."

GP FUNDING

GP practices are small businesses - and contracts are held by the practice, rather than individual GPs.

Funding comes from a number of different sources and is weighted so a practice with, say, lots of elderly people on its books will receive more than one which looks after a relatively young and healthy population.

The main source of income, accounting for around half the funding a practice receives, is the 'global sum'. This is a payment based on the estimated workload from the patients registered.

Next comes QOF - the Quality and Outcomes Framework which is at the centre of these latest contract changes.

This is in effect a points system where practices accumulate a score from meeting requirements such as monitoring how many of their patients have a certain condition or ensuring checks such as blood pressure readings are carried out on a regular basis.

These contract changes would cut QOF - and move funding of around £290m into the global pot.

Other funding streams include extras services such as flu and childhood jabs, which are not part of the contract but which most offer, are funded separately.

Seniority payments for long-serving GPs, and funding for premises make up the rest of a practice's income.

Out of this pot, a practice has to pay staff costs and other bills - as well as GPs' pay.

Those GPs who have responsibilities for practice management earned on average across the UK £103,000 in 2011/12.

Salaried GPs, who do not, could this year earn a maximum of £81,969.

In return, doctors have been freed from what they considered some of the most burdensome aspects of the form-filling they had to do for their performance-related pay.

This means requirements such as having to annually ask men with diabetes if they experienced erectile dysfunction at their check-ups will be removed, as will the need to ask those with high blood pressure in detail about their activity levels, with what doctors say were often irrelevant questions.

But Labour's Shadow Health Secretary Andy Burnham told BBC Radio 4's Today programme: "The bottom line is under this government, it has got harder to get a GP appointment. And nothing in today's announcement will correct that.

"People will still face the frustration of phoning the surgery at nine o'clock in the morning, being told there's nothing available for days and then some having to turn to A & E."

He added: "David Cameron cut Labour's scheme of evening and weekend opening and the guarantee of seeing a doctor within 48 hours," Mr Burnham added.

"This announcement will not put an end to patients phoning the surgery at 9am and finding it impossible to get an appointment - many of whom, not happy with a phone consultation, will still turn to A&E.

"People will fail to see how this package delivers the public commitment David Cameron gave last month to keep GP surgeries open from 8am to 8pm."

Dr Richard Vautrey of the British Medical Association's GPs committee, told the BBC: "It will help to a degree. It certainly won't be a panacea but it will start to focus on the needs of the most vulnerable and those patients who do go into hospital more frequently.

"And it will give GPs that bit more time to be able to spend with their patients to try and meet their needs."

mengele plus

Saturday, 7 December 2013

ancient humans

Saturday, 7 December 2013