Comments on: How a quarter of the cow genome came from snakes

By: Martin J Sallberg

Martin J Sallberg — Sat, 27 Apr 2013 11:07:54 +0000

The same ticks biting both cows and snakes, as well as cows occasionally eating snakes, are relatively small amounts of biological material transfered, and yet it has such a dramatic DNA impact. Then imagine how much DNA must be transfered between different cells in the same body! Goodbye, Weismann’s barrier, and welcome, soma-to-germline gene transfer.

By: A Amor

A Amor — Sun, 27 Jan 2013 11:07:17 +0000

Not many people know that cows (and other farm animals) eat meat. Living on a farm as a child I saw cows eat mice , rats and snakes. It is not common but it does happen.
A quick search on the web I found this story from 1910 in Australia

COW EATS SNAKE.

MORTLAKE, Wednesday-An unusual sight was witnessed at Framlingham on Tuesday by two men engaged in erecting fences they killed a snake in the morning and hung it on the fence Some few hours afterwards they saw a cow chewing a snake, some eighteen inches of which was hanging out of the animal’s mouth.
http://trove.nla.gov.au/ndp/del/article/10835757#pstart358167

By: Frankyv

Frankyv — Sat, 19 Jan 2013 12:39:01 +0000

Very interesting work here. Makes me think of a question I never asked in my biology class:
If C.elegans behavior can be affected by eating E.coli bacteria expressing a silencing DNA structure (RNAi), should I conclude that MY DNA profile – or transcriptome in worst case – potentially can be changed by eating food. Any, normal, regular, daily food?

By: Patrick Fay

Patrick Fay — Tue, 08 Jan 2013 21:50:15 +0000

Forgive me – I have no training in biology. But I have a couple of questions.

First – when you say that “between 10 and 11 percent of the cow genome consists of BovB,and a further 14 to 15 percent are descendants of this jumping gene,” does this mean that the stated percentages represent the percentage of DNA coding represented by these genes in each member of a population, does the percentage represent a sort of weighted average over the DNA information represented throughout the individuals of a species, or is there another meaning to these percentages? If the jumping gene information is present in substantially all members of a given species it would seem to have had to jump into a common ancestor at a time determinable based on analysis of the variation of this material throughout the population. Has this been done?

Is there a way to determine whether a particular portion of DNA actually has no effect on an organism or is this simply an educated guess? Is it possible to decide if a portion of coding is inert by detecting a different rate of change through mutation (i.e., more mutations may remain within useless info as any change that is not actively harmful would seem to be preserved over time as opposed to changes to consequential genes where overtly harmful changes would be eliminated as well as changes which reduced efficacy or eliminated efficacy)? Thank you – the article is fascinating. If these questions aren’t a waste of your time I have more.

By: Whatever Dude

Whatever Dude — Fri, 04 Jan 2013 04:12:10 +0000

Nobody knows what BovB does. My guess is that it’s an antibacterial or other microscopic-level process.

By: Mr. Ponderer

Mr. Ponderer — Thu, 03 Jan 2013 15:29:04 +0000

I was left with two questions I wonder if you might briefly answer:

1. What is the particular function of BovB that its usefulness is limited to a single species (i.e. snakes or cows)? Is it inert in any case, or is there a cross-species function?

2. What is the line of division between repetition that represents pointless or harmful aggregation, vs. useful duplication (e.g. backup)?

By: Cmdr. Awesome

Cmdr. Awesome — Wed, 02 Jan 2013 23:53:02 +0000

@David Adelson – Definitely more data would be needed. I’d not really thought closely about tick infestations carried on migratory birds but given the enormous flight range some of them have, I can see that being a viable transition vector.

From a layman’s point of view (namely mine) the whole situation dovetails so nicely w/continental drift, that I just got a bit carried away with that idea.

By: Dave Sands

Dave Sands — Wed, 02 Jan 2013 22:29:39 +0000

Ah. GMO’s are mentioned
For both sides of my 2 cents here we go. The proponents of GMO’s can prove their point if they open a restaurant that only serves GMO food, “better” food that has protein with three times as much essential amino acids, no toxins, no pesticides, high omega-3′s and full of golden vitamins, no carcinogens, etc, and flavor.. This is probably possible and this is the real potential of genetic engineering. Lots of traits can be inserted in tandem. In a short time the restaurant would be a big hit.
It is high time the engineers put up.
The restaurant could be named GMO for genetic engineered only.

By: Jonathan Eisen

Jonathan Eisen — Wed, 02 Jan 2013 21:11:01 +0000

Well, this is certainly a very interesting PROPOSED case of horizontal transfer and the results are very interesting.

However I dispute the statement you make “The only other explanation for these bizarre patterns is that BovB jumped between species, and it must have done so at least 9 times during its history—far more than the one or two jumps that other scientists had envisaged.”

This is without a doubt not the only other explanation. I can think of many things worthy of testing here as other possibilities including ancestral polymorphisms, convergent evolution, random noise (if you analyze 1000s of genes in organisms and a few show unusual patterns in phylogenetic trees is seems reasonable to conclude that this could just be statistical noise and not signal of any evolutionary event), ancient duplication of transposable element families and misidentification of orthology/ paralogy, bad sequence alignments, inaccurate phylogenetic tree inference, and many more.

I am NOT saying the authors theories are wrong. But this is a somewhat extraordinary claim. And I think it requires one to test ALL reasonable theories to explain the pattern, not just one or two.

By: Brandon

Brandon — Wed, 02 Jan 2013 20:09:11 +0000

So essentially, the next time I’m bitten by a blood-sucking insect, I should bear in mind that in addition to sucking out my life-blood and giving me malaria, it may ALSO be fundamentally altering my DNA to incorporate a bacterial symbiote it picked up off a squirrel or something.

Brb buying bug-spray.