4 things to know about epigenetics + Foster's rule explains tiny stature of ‘Hobbit’

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4 things to know about epigenetics, including that most changes are not passed on to offspring

INTRO: The concept of epigenetics is one that is easily misunderstood and even misused. This is obvious from premature claims that we epigenetically inherit the trauma of our ancestors or that epigenetics explains so-called past-life experiences. With epigenetics being increasingly evoked online and in the pages of the latest bestsellers, it’s important to explore what is actually known about the topic. While New Age entrepreneurs such as Deepak Chopra speak with confidence about being able to harness the powers of the epigenome for the benefits of human health, we need to keep in mind that far more is unknown about epigenetics than is known. Let’s have a look at what we do know. (MORE)

COVERED: 1 – Cell specialization depends on epigenetics ... 2 – The epigenome can be altered by outside influence ... 3 – Most epigenetic changes only affect the individual and are not passed on ... 4 – Some epigenetic marks are passed to offspring

Fast evolution explains the tiny stature of extinct ‘Hobbit’ from Flores Island

EXCERPT: . . . in 2004, ... archaeologists uncovered some very well-preserved fossil remains in the Liang Bua cave on Flores Island, Indonesia. The diminutive size of this new human species, Homo floresiensis, earned it the nickname “Hobbit.” ... After 15 years of intense research, anthropologists now confidently date the Liang Bua individual to have lived between 60,000 and 90,000 years ago. Her much older cousins in Flores lived 700,000 years ago. This long reign testifies to the success of this tiny human species, no matter how small-statured and small-brained they were. And this year anthropologists found a new dwarfed human species, christened Homo luzonensis, in the Philippines. So why did tiny humans wind up living on these islands? For us biogeographers and evolutionary biologists, the answer was right in front of us: the island rule.

[...] The Hobbit’s most likely ancestor is Homo erectus, a species more than twice its size in terms of its brain and overall bulk. Based on the geological history of Flores and the oldest known fossils of Homo floresiensis, it seems the evolution of the new species must have occurred in less than about 300,000 years. As evolutionary biologists, we are acquainted with the idea that Darwinian evolution is a slow and gradual process that takes place over very long timescales. Could such drastic change in body size happen this fast?

[...] We started our simulations assuming that large-bodied Homo erectus arrived at the island and then evolved into a smaller species there. Since we just don’t know the exact numbers our model should crank through, we based them on estimates obtained from current human populations. Because of this uncertainty, we ran our model thousands of times, each time using a random combination of all the parameters. Ultimately we were able to build a statistical distribution of how long it took for Homo erectus to become as small as Homo floresiensis.

After running 10,000 simulations, we were surprised to discover that in less than 350 generations, the process was complete. Thinking in terms of years, assuming a young female delivers a first baby at the average age of 15, that translates to about 10,000 years. [...] Of course we do not expect that all the features that make Homo floresiensis as unique as it is evolved that fast and at the same time. Yet, our simulation still shows, 300,000 years is far more than enough time for a new human species to arise. (MORE - details)

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