DNA in dinosaur bones

A recent study published in Bone (doi:10.1016/j.bone.2012.10.010) shows evidence of residual dinosaur DNA in dinosaur bones. They retrieved osteocytes (bone cells) from the bone and stained it for DNA.

The dinosaurs were Tyrannosaurus rex and Brachylophosaurus canadensis.

Row 1 (ABC) is T. rex. Row 2 (DEF) is B. canadensis. Row 3 (GHI) is ostrich.

Column 1 (ADG) is a anti-DNA antibody stain. Column 2 (BEH) is propidium iodide, a DNA stain. Column 3 (CFI) is 4′,6′-diamidino-2-phenylindole dihydrochloride, a DNA stain.

Note that the stains are limited to the nucleus of the cell.

They also identified several proteins including histones which are closely associated with DNA.

They have not yet sequenced the DNA, though that would be of considerable interest.

Christianity and homosexuality. Part 1

A Christian friend of mine (with no significant internet presence that I am aware of) has asked me about homosexuality. His basic question, embedded in a longer email, was:

I can’t see why God would have a problem with homosexuality, assuming that is was ‘good’ homosexuality. We have many, many examples of ‘bad’ heterosexuality. If we take all of what we say a monogamous, loving, ‘Godly’, heterosexual marriage should be and call that a ‘good’ relationship then I can’t see any difference if you just slotted in the word homosexual instead of heterosexual (except, obviously, you can’t have kids – leaving homosexual adoption etc aside). It’s not a matter of homosexuality means the population won’t grow or be able to look after us in our old age – as was the case in Biblical times.

Part of the difficulty answering this is that he is familiar with various other Christian controversies and observes that many people just quote mine Scripture to support their view. This can be true at times, parts of the Bible are used to hold up a prefabricated structure rather than the entire Bible forming the foundation and walls. Such an approach to Scripture can be a temptation, though I would argue that many Christians try to reframe their thinking from Scripture. Therefore he is not that interested in a list of verses refuting homosexuality as others could just offer an alternative list. Though I think finding verses showing the acceptability of homosexual behaviour and unions from Scripture is difficult, I will address the larger issue as I see it.

The arguments that homosexual behaviour is iniquitous comes from both general and specific revelation: nature and scriptural commands against it. Understanding the broader intentions of God gives reasons for these commands. I will initially post on general revelation, specific general revelation, and what could possibly be titled allegory.

The natural argument is significant. Christians know that the world is designed and hence purposeful. Teleology is asserted though variably understood. The natural anatomy of men and women is clearly complementary. The main purpose of the penis and the sole purpose of the vagina is coitus. The gonads are anatomically and functionally associated with them. The urethra is a conduit for urine, but its position is related to the presence of a penis, it merely needs to exit the body from the bladder and its location seems convenient. The uterus (womb) is anatomically intermediate between the vagina (coitus) and ovaries (reproduction). An anatomical connection is a biological necessity. The uterus is also functionally associated with the ovaries with regard to reproduction.

This knowledge of both the anatomy and the function of the sex organs in relation to coitus and reproduction demonstrates that men and women were designed complementary. This does not deny that an organ can have duel function, such as taste and speech with the tongue. Nor that an activity is restricted to a single function. Eating brings sustenance and pleasure. Coitus can give pleasure, produce intimacy, and create life. The point is that nature shows us that heterosexual coitus is how humans were designed to operate. To argue for sodomy (heterosexual or homosexual) one would need to show how such an activity is part of human design: a duel function analogous to the tongue being a taste organ as well as a speech organ.

Part 1. Part 2. Part 3. Part 4.

Inside the cell

This video is an animation of cellular activity. The animators tried to make the cells and cellular structures true to life. Colour is added, and there is more space in the animation: cells are packed full and structures would be difficult to discern with an accurate spatial rendering, though shape and scale are probably accurate.

What struck me first on seeing this, other than the cell being sublimely impressive, was that God must have had such a fun time designing life. It must have brought him so much pleasure.

More on the making of this animation here.

A longer 8 minute video with commentary available here. Well worth the time.

In your faces evolutionists

We have been long told that most of the DNA we have is junk, useless leftovers with no function after millennia of mutation and selection. Apparently only gene coding DNA is functional. Thus it was in the 1980s, and 1990s, and even 2000s though some of the more astute were suspicious.

The creationists were more circumspect. Perhaps gene coding DNA was a small component of the genome but, they protested, all that DNA is there for a reason. We are designed and we are very complicated. Our lack of knowledge does not preclude that the rest of the DNA is functional, we just aren't finished looking. So the junk DNA scenario was disputed by creationists decades ago. Pseudogenes, they said, probably had a function and were not left over relics from our primate, mammalian or reptilian past. Other codes beyond the triplet codon to amino acid likely existed.

This week Nature published 6 papers of several they aim to publish on the ENCODE project, along with other related material at their site.

The publication has made this news though much of this kind of information has been known to several researchers. The importance of introns has been known for some time. That polymerases produce far more RNA than is translated into protein is documented, even if the reason the this has been elusive. Gene regulators and promoters have been known of for decades, though it turns out that enhancers do not exist solely adjacent to the gene, but at distances of hundreds of thousands of bases distant. Why? Well because the 3 dimensional configuration of DNA means that a distant "file" location may happen to be physically nearby.

Interestingly the design advocates were long claiming unknown function for junk DNA. After all, while a few mutations have accumulated since creation, 95% of our genome housing junk is not consistent with design, even broken design. Creationists were dismissed, but it turns out they were correct all along. And the evolutionists who insisted that our genome was predominantly junk are left looking the fool. So much for the off quoted adage,

Nothing in biology makes sense except in the light of evolution.

Though I don't expect them to be questioning their dogma soon, rather adding some evolutionary spin,

Why evolution would maintain large amounts of 'useless' DNA had remained a mystery, and seemed wasteful. It turns out, however, that there are good reasons to keep this DNA.

Dragonfly aerodynamics

It has been questioned why dragonflies have 2 sets of wings. 2 pairs of wings add nothing to lift, it is thought the second pair decreases lift, nor manoeuvrability. Instead of an second set of wings, flies have halteres which function as gyroscopes and give them significant manoeuvrability. Dragonflies are still highly manoeuvrable—they can appear stationery from the vantage of their moving prey—they may just use a different mechanism to flies.

Modelling of dragonfly flight suggests that 2 sets of wings can decrease energy requirements if they beat out of phase.

Despite efforts at understanding the implications of flapping flight with two pairs of wings, previous studies have generally painted a rather disappointing picture: interaction between fore and hind wings reduces the lift compared with two pairs of wings operating in isolation. Here, we demonstrate with a mechanical model dragonfly that, despite presenting no advantage in terms of lift, flying with two pairs of wings can be highly effective at improving aerodynamic efficiency. This is achieved by recovering energy from the wake wasted as swirl in a manner analogous to coaxial contra-rotating helicopter rotors. With the appropriate fore–hind wing phasing, aerodynamic power requirements can be reduced up to 22 per cent compared with a single pair of wings, indicating one advantage of four-winged flying that may apply to... dragonflies...

So a second pair of wings decreases the energy requirements of dragonflies by a significant amount. A useful design feature and seen elsewhere in the biosphere—V formation bird flight decreases energy requirements by half by decreasing drag.