LaMarck Vindicated

If you wait long enough?   I havealready posted at some length on this topic, but this particular bit is anoutright vindication of Lamarck.

I also expect intelligent design to also be vindicated, but not quite theway the religious crowd would like.  It turnsout that an alternative source of intelligence is readily available and whentheir intellectual environment changes that they respond as best they may.

It is going to take a while to rewrite all those text books again but yourtake home is that natural selection is helped along by intelligent parentsconstantly improving their chances against a hostile world.  Makes way more sense than God rolling the dice!

For students of the history of science, the irony is rich.  No reputations are left intact.

You Are What Your Father Ate

by StaffWriters

Worcester MA(SPX) Dec 29, 2010

Scientists at the University of Massachusetts Medical School and the Universityof Texas at Austin have uncovered evidence that environmental influencesexperienced by a father can be passed down to the next generation,"reprogramming" how genes function in offspring. A new studypublished this week in Cell shows that environmental cues-in this case,diet-influence genes in mammals from one generation to the next,evidence that until now has been sparse.

These insights,coupled with previous human epidemiological studies, suggest that paternalenvironmental effects may play a more important role in complex diseases suchas diabetes and heart disease than previously believed.

"Knowing whatyour parents were doing before you were conceived is turning out to beimportant in determining what disease risk factors you may be carrying,"said Oliver J. Rando, MD, PhD, associate professor of biochemistry andmolecular pharmacology at UMMS and principal investigator forthe study, which details how paternal diet can increase production ofcholesterol synthesis genes in first-generation offspring.

The human genome isoften described as the set of instructions that govern the development andfunctioning of life. It's not surprising, then, that most contemporary geneticresearch focuses on understanding and cataloging how mutations and changes toour DNA-the basis of those "instructions"-cause disease and impacthealth.

A number of recentstudies, however, have begun to draw attention to the role epigeneticinheritance - inherited changes in gene expression caused by mechanisms otherthan changes in the underlying DNA sequence - may play in a host of illnesses."A major and underappreciated aspect of what is transmitted from parent tochild is ancestral environment," said Dr. Rando. "Our findingssuggest there are many ways that parents can 'tell' their childrenthings."

To test theirhypothesis that environmental influences experienced by the father can bepassed down to the next generation in the form of changed epigeneticinformation, Rando and colleagues fed different diets to two groups of malemice. The first group received a standard diet, while the second received alow-protein diet.

To control formaternal influences, all females were fed the same, standard diet. Rando andcolleagues observed that offspring of the mice fed the low-protein dietexhibited a marked increase in the genes responsible for lipid and cholesterolsynthesis in comparison to offspring of the control group fed thestandard diet.

These observations areconsistent with epidemiological data from two well-known human studiessuggesting that parental diet has an effect on the health of offspring. One ofthese studies, called the Overkalix Cohort Study, conducted among residents ofan isolated community in the far northeast of Sweden, found that poor diet duringthe paternal grandfather's adolescence increased the risk of diabetes, obesity and cardiovascular disease in second-generationoffspring.

However, because thesestudies are retrospective and involve dynamic populations, they are unable tocompletely account for all social and economic variables. "Our studybegins to rule out the possibility that social and economic factors, ordifferences in the DNA sequence, may be contributing to what we'reseeing," said Rando. "It strongly implicates epigenetic inheritanceas a contributing factor to changes in gene function."

The results also haveimplications for our understanding of evolutionary processes, says Hans A.Hofmann, PhD, associate professor of integrative biology at the University of Texasat Austin and aco-author of the study. "It has increasingly become clear in recent yearsthat mothers can endow their offspring with information about the environment,for instance via early experience and maternal factors, and thus make thempossibly better adapted to environmental change.

Our results show thatoffspring can inherit such acquired characters even from a parent they havenever directly interacted with, which provides a novel mechanism through whichnatural selection could act in the course of evolution." Such a processwas first proposed by the early evolutionist Jean-Baptiste Lamarck, but thendismissed by 20th century biologists when genetic evidence seemed to provide asufficient explanation.

Taken together, thesestudies suggest that a better understanding of the environment experienced byour parents, such as diet, may be a useful clinical tool for assessing diseaserisk for illnesses, such as diabetes or heart disease.

"We often look ata patient's behavior and their genes to assess risk," said Rando. "Ifthe patient smokes, they are going to be at an increased risk for cancer. If the family has a long history of heart disease,they might carry a gene that makes them more susceptible to heart disease. Butwe're more than just our genes and our behavior. Knowing what environmentalfactors your parents experienced is also important."

The next step forRando and colleagues is to explore how and why this genetic reprogramming isbeing transmitted from generation to generation. "We don't know why thesegenes are being reprogrammed or how, precisely, that information is beingpassed down to the next generation," said Rando.

"It's consistentwith the idea that when parents go hungry, it's best for offspring to hoardcalories, however, it's not clear if these changes are advantageous in thecontext of a low-protein diet."

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