Tom writes:
Greetings,
TWiEVO is a pleasure. But many of us don’t know when the Livestream comes up, and we miss the opportunity for real-time interaction.
Is there some way of posting ahead of time (even by a day) when livestream would be? Is there a notification list? Neither Vincent’s YouTube website, nor MicrobeTV.com have specific information, other than it’s generally once month, sometimes Monday, or Wednesday, 11 AM, sometimes 1 PM, Eastern Time.
Hoping to catch the next one!
Best regards,
Tom Steinberg
Thomas H. Steinberg, Ph.D.
Eugene, OR
Deadwood, OR
Jim writes:
Excellent episode with Alex Cagan #77.
Quick question for Nels Elde re: Lewontin study 50th anniversary
In the past 20 years there has been a lot of research on germ-line inheritance involving molecules other than those found specifically in base-sugar-phosphate (i.e. deoxyribonucleic acid ) i.e. cytosine, adenine, thymine, guanine, i.e. DNA. We now have a broad awareness of the presence of histones in an inherited genetic package and also knowledge of the prevalence of heritable post-translational modifications to all components of heritable material. The human genome (DNA bases alone) may be a non-issue in relation to race (per Lewontin’s 50-year-old study) but germline epigenetics (above the gene – above the DNA itself – above the CGTA) may be a big issue re: human difference and specifically racial differences. Why is there never any discussion of the effect on phenotype of epigenetic realities of heritable material?
There is ALWAYS confusion these days when the word “genetic” is spoken / written – does this mean the bases only or the bases plus methylations (adenylylation, citrullination, etc etc ) Is a gene a stretch of bases or a stretch of bases plus heritable modifications -modifications that may be conserved for thousands (millions) of years?
We all love the idea that humans are genetically identical (Lewontin’s idea) as as far as bases are concerned – we obviously ARE…..but what are the effects of all the other heritable additions to the DNA itself. There is an octamer of histones evey 126 bases – a lot of heritable stuff with all manner of avenues for difference.
Why does cutting edge bioscientist Nels Elde go all warm and fuzzy on Lewontin’s observation ignoring 20 years of germline epigenetics? Why not celebrate human difference. Harvard professor Howard Gardner discusses seven types of human intelligence – perhaps there is a heritable component to these differences?
Thank you for the superb series ! TWIV, TWIM, TWiEVO
All Best,
Jim Blake, Harvard GSD ’79
author: Distill the Zeit, The Bliss Engine, Station Point
Eric writes:
TWIEVO 77 with Alec Cagan was another amazing episode. The demonstration that somatic mutation rates were reduced in large, long lived, animals presumably to decrease the risk of developing cancer was very elegant. The discussion made me wonder whether the tissues collected over sequential generations of mice could similarly be used to measure the rate of epigenetic “mutation” using sequencing tools that detect DNA methylation? Could inheritable epigenetic changes in germ lines provide a faster mechanism of evolution than traditional changes at the nucleotide level? Can new methylation patterns in germ lines be considered the functional equivalent of DNA mutations if they affect gene expression?
Curious
Eric Delwart