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Changes in life history are expected when new sources of extrinsic mortality impact on natural populations. We report a new disease, devil facial tumor disease, causing an abrupt transition from iteroparity toward single breeding in the largest extant carnivorous marsupial, the Tasmanian devil (Sarcophilus harrisii), in which males can weigh as much as 14 kg and females 9 kg. This change in life history is associated with almost complete mortality of individuals from this infectious cancer past their first year of adult life. Devils have shown their capacity to respond to this disease-induced increased adult mortality with a 16-fold increase in the proportion of individuals exhibiting precocious sexual maturity. These patterns are documented in five populations where there are data from before and after disease arrival and subsequent population impacts. To our knowledge, this is the first known case of infectious disease leading to increased early reproduction in a mammal. The persistence of both this disease and the associated life-history changes pose questions about longer-term evolutionary responses and conservation prospects for this iconic species.
At this stage, all we have evidence for is a phenotypic response.
Then if the young inherit antibodies or immunity is this an acquired trait?
It's notable that in humans too, we tend to breed before we get old enough to get cancer.
EchoIf anything is going to be able to show lamarckism (even though I doubt anything would) it is could be a strange fact set as this; HOWEVER from the paper:QuoteAt this stage, all we have evidence for is a phenotypic response. I have not read the paper thoroughly but I could not find any mention of the genetic change that you mention. the strange circumstances have lead the authors to say that this we may be able to observe rapid adaptation. at no point do the authors even posit the notion that genotype passed onto progeny may be different from that of the parents.this is definitely not proof of lamarckism - the only evidence so far is phenotypical; although a darwinian response is clearly hinted at and expected.Quote from: echochartruse on 07/07/2010 08:20:13Then if the young inherit antibodies or immunity is this an acquired trait?Infants can acquire antibodies from their mother (just as we do) but this is due to shared systems and not genetic. on acquired immunity; there is a lack of diversity in tassies, especially in the major histopathological complex and this hampers the ability to fight disease. those individuals with a better immune response are more likely to breed than those without - this is darwinism, even if at an increased rate.Matthew
I've explained this in the other threads.The disease is driving a population structure change. This in itself has nothing to do with DNA.A result of the population structure change is that different individuals have breeding access (in this case, younger individuals). As a result, one would expect to see genetic changes in the population.
Yes there is limited phenotypic variability. It is under stress these animals are changing and Lamarckan inheritance allows quicker genetic adaptation to new environment which has happened in the Tassie Devils, as I see, with entire populations breeding earlier because of their contagious fatal disease.
Isn't the ability for the Tassie Devils to breed earlier genetic?Isn't this both epigenetic and genetic.
Chance through random mutations in an organism's doesn't explain how rare mutations can help organisms of every size and variety adapt quickly enough through time.
Only time will tell if antibodies found in one devil that is passed on, want this show a Lamarchian inheritance? These animals have no antibodies at present, they are virtually clones.
At this stage, all we have evidence for is aphenotypic response. We suggest that DFTD is a novel, strongselective agent for life-history change that might lead to rapidadaptation toward a population genetically and demographicallymore robust to the effects of DFTD.To our knowledge, this is the first known case of infectiousdisease leading to increased early reproduction in a mammal.
We suggest that DFTD is a novel, strongselective agent for life-history change that might lead to rapidadaptation toward a population genetically and demographicallymore robust to the effects of DFTD.
Your two quotes explain why this is not Lamarckism. The first quote deals with a reaction based on phenotype - ie this is genetic-change neutral. genetically identical animals react differently in different environments. This CANNOT be lamarckism as there is no genetic change. The second quote shows that the researchers expect, in time, that darwinian evolution will occur more rapidly than usual. this is adaptation through natural selection; those animals with a 'useful' genotype breed more.
strong larmarckism states that an individual animal can alter its genotype in response to an environmental factor; this is generally accepted as untrue and impossible.
in a truer sense of the idea that was originally propounded it is claimed that over generations the gene pool of a species will adapt to environmental pressures without natural selection of beneficial genes through differential rates of breeding. neither of these have ever been proved or any real evidence put forward in their favour other than anecdote. the fact that it is difficult to comprehend how the complexity of nature can arise without a guiding hand or designer is one reason that darwin is so celebrated, the idea is ground breaking, counter-intuitive and yet able to withstand all challenges so far. evolutionary timescales are normally so vast that the short-lived human might have trouble understanding the concept - the unusual situation in tasmania means that we will be able to observe (still over many many years) the first stages of adaptation of a mammal in the wild. it is difficult not to be amazed by evolution through natural selection if you have properly understood it - but there is nothing in the complexity of life that is not explained by it. there is no need to search for a design or the hand of a creator.
any alternative theory must advance by showing a fact set that cannot be explained by darwinian evolution and can be explained by the new alternative; the predictions made by any new theory can then be tested. darwinian evolution is the subject of rigorous and regular challenge and has not be found to be flawed yet, despite the huge effort and resources placed in the hands of ideologically motivated opponents. matthew
phe∑no∑type (fn-tp)n.1.a. The observable physical or biochemical characteristics of an organism, as determined by both genetic makeup and environmental influences.b. The expression of a specific trait, such as stature or blood type, based on genetic and environmental influences.2. An individual or group of organisms exhibiting a particular phenotype.
Bacteria Mutate Much More Than Previously Thought
OK, it is not Lamarckism.Again, Isn't maturing earlier to breed genetic?
could you explain a mechanism (even if a bit hand-wavy) of how a mother that contracts a form of cancer can pass a different and advantageous genotype to her progeny. this is necessary to accept lamarckism.
strong larmarckism states that an individual animal can alter its genotype in response to an environmental factor
Genes May Explain Why Children Who Live Without Dads Have Earlier SexMendle and her colleagues looked at more than 1,000 cousins ages 14 and older from the National Longitudinal Survey of Youth. The study design tested for genetic influences as well as factors such as poverty, educational opportunities, and religion. It compared children who were related in different ways to each other, and who differed in whether they'd lived with their fathers. The more genes the children shared, the more similar their ages of first intercourseóregardless of whether or not the children personally had an absent father. This finding, the researchers say, suggests that environmental theories don't fully explain the puzzle. Instead, genetic influence can help us understand the tie between fathers' absence and early sex.
Cornell Sheep Program researchers have discovered an unusual form of a gene that prompts ewes to breed out of season as well as conceive at younger ages and more frequently.http://www.sciencedaily.com/releases/2009/08/090806112401.htm
OK but non competition in captivity does not result in breeding earlier. The zoos here have very good facilities and food is plentiful. Limited and controlled numbers of male to females, but never has it been recorded that they matured earlier to breed. This is documented as a result of their disease.
Contrary to your ideas I believe that the Devil's ability to mature early is not a decision made by them by choice but rather governed by genetics.
Contrary to your ideas I believe that the Devil's ability to mature early is not a decision made by them by choice but rather governed by genetics. These are not my ideas! Evolution through natural selection is basic science. To challenge this you need to provide a mechanism, even very basic one, of how this might happen. Without need to rehearse details and bio-chemical pathways, and in the most hand-wavy way; how does a mother pass on a genetic inheritance to her off-spring that has been changed to meet environmental pressures and is not solely determined by her parents' dna?Matthew
how does a mother pass on a genetic inheritance to her off-spring that has been changed to meet environmental pressures and is not solely determined by her parents' dna?
I find it weird that both Lamarck and Darwin never knew about DNA,neither did anyone else until quiet recently yetwe must prove DNA is not involved in phisycal change to accept or dismiss either theory.
phenotype is determined by both genetic and environmental influences.The devil's situation is discribed as phenotype.
Yes, I accept 'Natural Selection'!.. Those that survive, survive. Those that don't, don't. It's so basic.
Like the Tibeans who have a specific gene turned on so they can cope with the altitude they live at.At one point in time, prior to our knowledge of DNA, one or possibly more Tibetans geneome changed, shuffling genes to meet their environmental pressures and since then this aquired trait has been inherited throughout the population who live there.
A taste (like or dislike) for a specific food can be aquired and geneticaly inherited.
Therefore, inheritance may be entirely about genes.
Lamarch and Darwin, not knowing about DNA would never have asked themselves this question.
BUT as we see from any evolution it only takes one to aquire the change in the genome for others to inherit this change depending on environment, lifestyle of course. What I am saying is that traits are aquired and inherited.