Pregnant T. rex may contain the holy grail of all dinosaur fossils: DNA

[sauroid]

A pregnant Tyrannosaurus rex has been found, shedding light on the evolution of egg-laying as well as on gender differences in the dinosaur.

http://mashable.com/2016/03/15/pregnant-t-rex-dna/#WjHUyhltL5q5

[tyrantqueen]

Now this is an interesting find.

[CityRaptor]

So maybe we will soon know if Sue is really female or "A boy named Sue" is the case.

I also expect comments about Jurassic Park on a few sites.

[SBell]

The one thing I didn't understand--why would there be genetic material/DNA just because there is medullary bone? Although it sounded like the author asked the question, but didn't get much of an answer--still, good enough to put in the headline.

And why 'pregnant'? Maybe 'gravid' or 'fertile' or 'fecund' or 'in-season'.

[PaleoMatt]

This is proving to be a great year already! Now we need dem feathers!

[Halichoeres]

The one thing I didn't understand--why would there be genetic material/DNA just because there is medullary bone? Although it sounded like the author asked the question, but didn't get much of an answer--still, good enough to put in the headline.

And why 'pregnant'? Maybe 'gravid' or 'fertile' or 'fecund' or 'in-season'.

I think it's because marrow has an unusually high quantity of DNA--in fact it's one of the few places where bone has any DNA at all. It's where blood cells are manufactured, so it's undergoing more cell division than almost any tissue, other than fast-rotting kidney or liver tissue. And of course, in archosaurs, unlike in mammals, the red blood cells have nuclei! I would guess chances are still pretty damn slim, but it's a better chance than, you know, amber.

[SBell]

The one thing I didn't understand--why would there be genetic material/DNA just because there is medullary bone? Although it sounded like the author asked the question, but didn't get much of an answer--still, good enough to put in the headline.

And why 'pregnant'? Maybe 'gravid' or 'fertile' or 'fecund' or 'in-season'.

I think it's because marrow has an unusually high quantity of DNA--in fact it's one of the few places where bone has any DNA at all. It's where blood cells are manufactured, so it's undergoing more cell division than almost any tissue, other than fast-rotting kidney or liver tissue. And of course, in archosaurs, unlike in mammals, the red blood cells have nuclei! I would guess chances are still pretty damn slim, but it's a better chance than, you know, amber.

I think the most important part to that is that the answer was artfully dodged with a 'we're still looking at it'. I'm guessing that the medullary bone was considered exciting enough. Except for the article author.

[amargasaurus cazaui]

This is also hardly groundbreaking up to the minute news either, this information has been around and had been published at least a few years back.It appears a tad...sensationalized..hence the term pregnant etc.

[alexeratops]

Everyone already essentially said my thoughts on this topic, so I won't bother with that. But I will say that when I read the title of this thread I started taking deep breaths...

[HD-man]

So maybe we will soon know if Sue is really female or "A boy named Sue" is the case.

See the Larson quote. Also, see Figure 8.18 for how they plot on a graph (Sue is FMNH PR2081): https://books.google.com/books?id=5WH9RnfKco4C&pg=PA125&dq=%22figure+8.18.+mor%22&hl=en#v=onepage&q=%22figure%208.18.%20mor%22&f=false ).

This is also hardly groundbreaking up to the minute news either, this information has been around and had been published at least a few years back.It appears a tad...sensationalized..hence the term pregnant etc.

My thoughts exactly.

Quoting Larson ( http://www.amazon.com/Tyrannosaurus-Tyrant-King-Life-Past/dp/0253350875 ):

By use of morphometric analysis, gracile and robust morphs are confirmed to be present within the clade Tyrannosaurus rex. Extant phyloge- netic bracketing (comparison with living crocodiles and birds) leads us to conclude that the existence of these 2 morphs most parsimoniously repre- sents sexual dimorphism. The discovery of medullary bone within the medullary cavity of a robust specimen of T. rex established MOR 1125 as female (Schweitzer et al. 2005), and therefore all other robust T. rex specimens are, in all probability, also female.

[CityRaptor]

Well, that explains why something about those "news" felt familiar.

[Loxodon]

By use of morphometric analysis, gracile and robust morphs are confirmed to be present within the clade Tyrannosaurus rex. Extant phyloge- netic bracketing (comparison with living crocodiles and birds) leads us to conclude that the existence of these 2 morphs most parsimoniously repre- sents sexual dimorphism. The discovery of medullary bone within the medullary cavity of a robust specimen of T. rex established MOR 1125 as female (Schweitzer et al. 2005), and therefore all other robust T. rex specimens are, in all probability, also female.

Now, I can't quite remember where I got this from, but I distinctly recall having heard that the robust and gracile tyrannosaurus morphs were found in different layers of the rock formations, with one of the two (don't recall which) being found primarily in the lower layers, while the other is found mostly in the upper. That would very, very heavily imply that the different morphs are actually chrono-populations or subspecies, rather than sexes or the like. If this is true, I am very curious as to whether the paper in question here took that into account when drawing their conclusion. If they did, or if I'm remembering all of this wrong, then this is an interesting conclusion indeed. If not however, I'd take their conclusion with a grain of salt to say the least.

[HD-man]

If this is true, I am very curious as to whether the paper in question here took that into account when drawing their conclusion. If they did, or if I'm remembering all of this wrong, then this is an interesting conclusion indeed.

IDK if that's true. Source(s)? In any case, it's been a while since I've read the paper & I currently don't have access to the whole thing, but from what I remember, it covers geographic/stratigraphic distribution on pages 106-114 & concludes, "Neither geographic nor stratigraphic distribution can explain these differences."

[Loxodon]

IDK if that's true. Source(s)?

Well that's the problem - as I said, I don't recall where I've gotten it from. I was hoping somebody else might have known something. If you are remembering right though, and the paper actually says that, then I suppose it does not much matter either way.

[SBell]

IDK if that's true. Source(s)?

Well that's the problem - as I said, I don't recall where I've gotten it from. I was hoping somebody else might have known something. If you are remembering right though, and the paper actually says that, then I suppose it does not much matter either way.

I know I had seen the idea--but any study (cursory or detailed) that I was aware was either inconclusive or dismissive of the 'separate species' idea. This current study appears to follow suit.