CONGRATULATIONS to jayman and mrs. jayman and their extended familiy members! (^_^)
what a cutie!: Meet JayMan Jr. (^_^)
CONGRATULATIONS to jayman and mrs. jayman and their extended familiy members! (^_^)
what a cutie!: Meet JayMan Jr. (^_^)
’cause (according to reddit) they make stuff like this:
i was already really impressed by the tibetans and their sky burials, but now they’ve truly surpassed themselves! (^_^)
Mysterious Chinese Fossils May Be New Human Species
“Mysterious fossils of what may be a previously unknown type of human have been uncovered in caves in China, ones that possess a highly unusual mix of bygone and modern human features, scientists reveal.
“Surprisingly, the fossils are only between 11,500 and 14,500 years old. That means they would have shared the landscape with modern humans when China’s earliest farmers were first appearing.
“‘These new fossils might be of a previously unknown species, one that survived until the very end of the ice age around 11,000 years ago,’ said researcher Darren Curnoe, a palaeoanthropologist at the University of New South Wales in Australia.
“‘Alternatively, they might represent a very early and previously unknown migration of modern humans out of Africa, a population who may not have contributed genetically to living people,’ Curnoe added….”
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more from dienekes.
(note: comments do not require an email. or are the red deer cave people “nothing extraordinary”?)
back in the 70s, michael wade ran an altruism experiment with some confused flour beetles.
confused flour beetle larvae have a tendency to cannibalize nearby eggs (’cause they’re confused? (~_^) ). wade wanted to find out if there were any differences in the cannibalization rates between more closely related versus not so closely related hatches. so, he outbred some groups of beetles and inbred other groups to see what would happen.
i don’t have access to the paper related to this research, but here’s a summary of what he found from another one of his papers [pgs. 844-45]:
“In experimental studies of kin selection, using laboratory populations of the flour beetle, Tribolium confusum, Wade (1980a) investigated the effects of discontinuities in population breeding structure on the predictions of kin selection theory. The experiment consisted of synthesizing a strain of T. confusum with genetic variability for the tendency of larvae to cannibalize eggs. Beetles randomly chosen from this strain were then placed in six different treatments, each representing a different population structure, and the evolution of the cannibalism behavior was followed for several generations….
“The population structure was varied by varying both the degree of genetic relatedness between the larval cannibals and their egg victims and the degree of random mating. Depending on the treatment, the genetic relationship between the larvae and eggs was .50 (full-sibs), .25 (half-sibs), or .00 (no relationship). These ‘interaction treatments’ were factorially combined with two different breeding structures, representing the extremes of (1) random mating and (2) within-group mating. Wade (1980a) observed that the egg cannibalism rates, which were initially equal, diverged significantly from one another only in the within-group mating treatments. Specifically, in that treatment where the larvae and eggs were full-sibs, cannibalism rates declined relative to the treatment where the larvae and eggs were unrelated. Cannibalism rates in the half-sib treatment were intermediate. In those treatments with random mating, however, no differences in cannibalism rates were observed regardless of the larval-egg relationship….
“On the basis of this comparison of two extreme mating systems, Wade (1980a) concluded that inbreeding should accelerate the rate of evolution of social behaviors.”
so, inbreeding makes the evolution of altruism (and other social behaviors) easier.
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digression. this research with bugs reminded of an amusing story from bill hamilton about doing research at the univ. of michigan and some other bugs [pg. 51]:
“I mathematized them [some models] as far as I could and then used simulation on the Michigan main computer, accessing it either from a huge cave-like room called NUBS in the basement of the herbarium (our nearest-neighbour building) or, later, from a smaller terminal room in my own floor of the Museum of Zoology. NUBS had firebrats plus a spectrum of dazed, earnest, and sometimes frighteningly expert freshmen. Freshmen are first-year university students; firebrats, not arsonists but primitive insects. Smartly striped like football players, the latter dashed swiftly about on the floor under the piles of unwanted output paper, especially favouring that mounded against walls. I think their name’s origin lies in their being commonly found near bakery ovens. The nature of their food there is obvious; but what it was under the paper in NUBS is hard to imagine unless perhaps there were mummified students, dead of their sorrow at their unco-operating programs.”
(^_^)
previously: technical stuff and even plants do it! and more plants playing favorites and even ROBOTS do it! and even monkeys do it and even slime molds do it!
(note: comments do not require an email. the beetles!)
just when you think you’ve got inbreeding and genetics sorted out in your head (almost — well, no, not really), they throw something new at ya.
here’s an article that linton @nobabies.net pointed out to me (thanks, linton!):
“Epigenetics Linked to Inbreeding Depression”
16 September 2011
“Inbreeding depression is the bane of conservation biology. When closely related individuals mate, which can happen when there aren’t too many members of a species left, their offspring are often less fit and less fertile, making the species all the more vulnerable. Both plants and animals can suffer from inbreeding depression, and textbooks typically attribute this phenonmenon to genetics: Recessive genes with harmful effects, whose negative influences are normally masked by a dominant copy of a gene, are more likely to pair up in offspring of more genetically similar parents.
“Or so the theory goes.
“But Philippine Vergeer, an evolutionary ecologist at Radboud University Nijmegen in the Netherlands, suspects that epigenetics — chemical modifications to the DNA that alter gene activity — may also be to blame, at least in plants….
“Vergeer and her Radboud colleagues Niels Wagemaker and Joop Ouborg compared DNA methylation between outbred and inbred S. columbaria — also known as small scabious — derived from the same mother plant. Methylation was 10% higher in inbred plants…. Also, inbred and outbred plants have different parts of their genomes methylated.
“The scientists then decided to look at what happened to plant offspring if they reconfigured the flora’s methylation. Every day for a week, they exposed germinating seeds of inbred and outbred plants to a demethylating agent. The result: ‘Phenotypic differences between outbred and inbred plants are nullified,’ Vergeer reported….”
so, at least in the case of these little plants, inbreeding depression seems to be connected to epigenetics and not genetics. when they reversed the epigenetics in these plants, the inbred plants photosynthesized (which is what the researchers were measuring) just as well as the outbred plants.
neato!
there has been some research done showing that epigenetic states are probably regulated (if that’s the right way to put it) by the underlying genetics, so perhaps the inbreeding depression in these plants was still a result of too many “bad genes.” but it’s cool that they could reverse the inbreeding depression by getting rid of the methylation!
there have also been studies, of course, showing that some epigentic states can be inherited across a few or several generations.
see also: Inbreeding and epigenetics: beneficial as well as deleterious effects
previously: the genetics of epigenetics
(note: comments do not require an email. squeek!)
biology is so cool:
“[F]or any woman that has ever been pregnant, some of her baby’s cells may circulate in her bloodstream for as long as she lives. Those cells often take residence in her lungs, spinal cord, skin, thyroid gland, liver, intestine, cervix, gallbladder, spleen, lymph nodes, and blood vessels. And, yes, the baby’s cells can also live a lifetime in her heart and mind.
“Here’s what happens.
“During pregnancy, cells sneak across the placenta in both directions. The fetus’s cells enter his mother, and the mother’s cells enter the fetus. A baby’s cells are detectable in his mother’s bloodstream as early as four weeks after conception, and a mother’s cells are detectable in her fetus by week 13. In the first trimester, one out of every fifty thousand cells in her body are from her baby-to-be (this is how some noninvasive prenatal tests check for genetic disorders). In the second and third trimesters, the count is up to one out of every thousand maternal cells. At the end of the pregnancy, up to 6 percent of the DNA in a pregnant woman’s blood plasma comes from the fetus. After birth, the mother’s fetal cell count plummets, but some stick around for the long haul. Those lingerers create their own lineages. Imagine colonies in the motherland….
“How many people have left their DNA in us? Any baby we’ve ever conceived, even ones we’ve miscarried unknowingly. Sons leave their Y chromosome genes in their mothers. The fetal cells from each pregnancy, flowing in a mother’s bloodstream, can be passed on to her successive kids. If we have an older sibling, that older sibling’s cells may be in us. The baby in a large family may harbor the genes of many brothers and sisters. My mother’s cells are in my body, and so are my daughter’s cells, and half my daughter’s DNA comes from her dad. Some of those cells may be in my brain….”
whoa.
wikipedia says (so it must be true): “After giving birth, about 50-75 % of women carry fetal immune cell lines. Maternal immune cells are also found in the offspring yielding in maternal→fetal microchimerism, though this phenomenon is about half as frequent as the former”
(note: comments do not require an email. chimera!)