zacharoo

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  • July 11, 2013
  • 02:10 PM
  • 225 views

Update: Brain growth in Homo erectus, and the age of the Mojokerto fossil

by zacharoo in Lawn Chair Anthropology

The Mojokerto calvaria. You're looking at the left side of the skull: the face would be to the left. Check it out in 3D here.A few months ago I posted an abridged version of the presentation I gave at this year's meetings of the American Association of Physical Anthropologists, about brain growth in Homo erectus. This study, co-authored with Jeremy DeSilva, adopts a novel approach (see "Methods" in that earlier post) to analyze the Mojokerto fossil (right). The specimen is the only H. ........ Read more »

  • June 19, 2013
  • 12:54 AM
  • 267 views

We like turtles ('s genomes)

by zacharoo in Lawn Chair Anthropology

June 2013, Volume 45 No 6 pp 579-714Jonathan the zombie isn't the only one who likes turtles. These heroes-in-a-half-shell adorn the cover of the current Nature Genetics, as two species of turtle have just joined the Genome Club (Wang et al. 2013; paper's free!).This definitely not one of those genome sequencing studies alluded to recently by John Hawks, that's "too boring for journals." Wang and colleagues didn't just sequence the genomes of soft-shell and green sea tur........ Read more »

  • May 12, 2013
  • 05:01 AM
  • 203 views

Online skeletal and dental datasets (links links links!)

by zacharoo in Lawn Chair Anthropology

Jean Jacques Hublin has a commentary [1] in the current issue of Nature, about making fossils available for scanning, digital replication, and ultimately hopefully open dissemination. As Hublin points out, it's a bit ridiculous that a fossil is a rare enough thing as it is, but even after their discovery, fossils "can become unreachable relics once they are in storage." Fortunately, Hublin goes on to point to online collections that are available to anyone interested. Somewhat ironically, t........ Read more »

  • May 11, 2013
  • 09:43 AM
  • 254 views

Arm and leg modelling

by zacharoo in Lawn Chair Anthropology

No, I'm not looking for people with lithe limbs to be photographed for money. Much more sexily, I'm referring to a recent paper (Pietak et al., 2013) that's found that the relative length of the segments of human limbs can be modeled with a log-periodic function:Figure 2 from Pietak et al. 2013. Human within-limb proportions are such that the length of each segment (e.g., H1-6) of a limb, from  fingertip to shoulder (A) and to to hip (B), can be predicted by a logarithmic periodic function&........ Read more »

  • April 16, 2013
  • 03:05 PM
  • 235 views

Pre-publication: Brain growth in Homo erectus (plus free code!)

by zacharoo in Lawn Chair Anthropology

The annual meetings of the American Association of Physical Anthropologists were going on all last week, and I gave my first talk before the Association. The talk focused on using resampling methods and the abysmal human fossil record to assess whether human-like brain size growth rates were present in our >1 mya ancestor Homo erectus. This is something I've actually been sitting on for a while, but wanted to wait til the talk to post for all to see. Here's a brief version:Background: Hu........ Read more »

Coqueugniot H, Hublin JJ, Veillon F, Houët F, & Jacob T. (2004) Early brain growth in Homo erectus and implications for cognitive ability. Nature, 431(7006), 299-302. PMID: 15372030  

Herndon JG, Tigges J, Anderson DC, Klumpp SA, & McClure HM. (1999) Brain weight throughout the life span of the chimpanzee. The Journal of comparative neurology, 409(4), 567-72. PMID: 10376740  

Sakai T, Matsui M, Mikami A, Malkova L, Hamada Y, Tomonaga M, Suzuki J, Tanaka M, Miyabe-Nishiwaki T, Makishima H.... (2013) Developmental patterns of chimpanzee cerebral tissues provide important clues for understanding the remarkable enlargement of the human brain. Proceedings. Biological sciences / The Royal Society, 280(1753), 20122398. PMID: 23256194  

  • February 28, 2013
  • 12:19 PM
  • 329 views

Go home, RNA, you're drunk

by zacharoo in Lawn Chair Anthropology

(Alternate title: "circRNA censors the RNA censors?")When I was a kid, RNA played second fiddle to DNA. RNA was a mere intermediary between the 'book of life' (DNA) and the stuff the book coded for (proteins). But in the years since, RNA has shown itself to be a key player in the regulation of gene expression (shut up, DNA!). We now know of lots of kinds of non-coding RNA (ncRNA) that do lots of important things in cells, such as maintaining genomic integrity in the germ line (piRNA) a........ Read more »

Hansen, T., Jensen, T., Clausen, B., Bramsen, J., Finsen, B., Damgaard, C., & Kjems, J. (2013) Natural RNA circles function as efficient microRNA sponges. Nature. DOI: 10.1038/nature11993  

Memczak, S., Jens, M., Elefsinioti, A., Torti, F., Krueger, J., Rybak, A., Maier, L., Mackowiak, S., Gregersen, L., Munschauer, M.... (2013) Circular RNAs are a large class of animal RNAs with regulatory potency. Nature. DOI: 10.1038/nature11928  

  • February 20, 2013
  • 10:49 PM
  • 317 views

The shale revolution & lying with statistics

by zacharoo in Lawn Chair Anthropology

Is U.S. energy independence, based in part on 'fracking' shale deposits to access oil and gas reservoirs, just a pipe dream? A comment by JD Hughes in this week's Nature posits just this, pointing out that production at most of these deposits declines steeply in just a few years - the industry is simply not sustainable. But why all the hype around such an unsustainable resource?In my view, the industry practice of fitting hyperbolic curves to data on declining productivity, and inferring li........ Read more »

  • February 2, 2013
  • 12:04 AM
  • 243 views

The "human" genome?

by zacharoo in Lawn Chair Anthropology

The topic this week in my Intro to Bioanthro course is genetics, with the subtheme being the mechanisms getting us from a genotype to "the" human phenotype (next week is variation and population genetics). Of course we talked about things like DNA, simple Mendelian inheritance (even though many traits/diseases probably aren't really Mendelian), and even epigenetics and genomic imprinting. But I also wanted to point out the many ways that our very existence relies of life extrinsic to that encode........ Read more »

Gilbert, S., Sapp, J., & Tauber, A. (2012) A Symbiotic View of Life: We Have Never Been Individuals. The Quarterly Review of Biology, 87(4), 325-341. DOI: 10.1086/668166  

Smith MI, Yatsunenko T, Manary MJ, Trehan I, Mkakosya R, Cheng J, Kau AL, Rich SS, Concannon P, Mychaleckyj JC.... (2013) Gut Microbiomes of Malawian Twin Pairs Discordant for Kwashiorkor. Science. PMID: 23363771  

van Nood E, Vrieze A, Nieuwdorp M, Fuentes S, Zoetendal EG, de Vos WM, Visser CE, Kuijper EJ, Bartelsman JF, Tijssen JG.... (2013) Duodenal infusion of donor feces for recurrent Clostridium difficile. The New England Journal of Medicine, 368(5), 407-15. PMID: 23323867  

Yatsunenko T, Rey FE, Manary MJ, Trehan I, Dominguez-Bello MG, Contreras M, Magris M, Hidalgo G, Baldassano RN, Anokhin AP.... (2012) Human gut microbiome viewed across age and geography. Nature, 486(7402), 222-7. PMID: 22699611  

  • January 28, 2013
  • 10:32 PM
  • 304 views

Open wide for open access: chimpanzee tooth eruption

by zacharoo in Lawn Chair Anthropology

Two anthropology papers came out yesterday in advance print at the Proceedings of the National Academy of Sciences. I'd like first to draw your attention to the fact that they're open access - normally such scientific papers are behind a paywall, but these two can be obtained by anyone (well, anyone with internet). One is about the chronology and nature of Acheulean technology at the 1.7-1.0 mya site of Konso in Ethiopia. The other, and the subject of this post, is about life history in wild chi........ Read more »

Smith TM, Smith BH, Reid DJ, Siedel H, Vigilant L, Hublin JJ, & Boesch C. (2010) Dental development of the Taï Forest chimpanzees revisited. Journal of human evolution, 58(5), 363-73. PMID: 20416929  

Smith, T., Machanda, Z., Bernard, A., Donovan, R., Papakyrikos, A., Muller, M., & Wrangham, R. (2013) First molar eruption, weaning, and life history in living wild chimpanzees. Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.1218746110  

Zihlman A, Bolter D, & Boesch C. (2004) Wild chimpanzee dentition and its implications for assessing life history in immature hominin fossils. Proceedings of the National Academy of Sciences of the United States of America, 101(29), 10541-3. PMID: 15243156  

  • November 27, 2012
  • 02:39 PM
  • 408 views

A new method for analyzing growth in extinct animals (dissertation summary 1)

by zacharoo in Lawn Chair Anthropology

The last year and a half was a whirlwind, and so I never got around to blogging about the fruits of my dissertation: Mandibular growth in Australopithecus robustus... Sorry! So this post will be the first installment of my description of the outcome of the project. The A. robustus age-series of jaws allowed me to address three questions: [1] Can we statistically analyze patterns of size change in a fossil hominid; [2] how ancient is the human pattern of subadult growth, a key aspect of our ........ Read more »

  • September 30, 2012
  • 01:45 AM
  • 319 views

Malaria, sickle-cell anemia and microRNA

by zacharoo in Lawn Chair Anthropology

This is the first time I'm teaching Introduction to Biological Anthropology here at Nazarbayev University. It's exciting and curious that for nearly every class session, I'm able to find a very recent outside article or blog post that's relevant to the field and/or something we're talking about at the moment. For instance, the 30-paper barrage of the ENCODE project came out right as we were beginning the unit focused on evolution and genetics. Serendipity!Recently in this first unit, w........ Read more »

  • August 22, 2012
  • 12:56 PM
  • 341 views

Bonobo survival strategy

by zacharoo in Lawn Chair Anthropology

A paper was just released that showcases the technological prowess of two captive bonobos (Pan paniscus), the famous Kanzi and the less famous Pan-Banisha (Roffman & al. in press). It's a neat paper, and I don't really have much to say about it, but I will pass on what I enjoyed most about it (abstract and keywords):What's the strategy - not living in the DRC? (sorry, too soon). But seriously, it sounds like a rock band or something. You don't see key words/phrases like that every day. ........ Read more »

Itai Roffman, Sue Savage-Rumbaugh, Elizabeth Rubert-Pugh, Avraham Ronen, & Eviatar Nevo. (2012) Stone tool production and utilization by bonobo-chimpanzees (Pan paniscus). Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.1212855109  

  • August 9, 2012
  • 03:32 PM
  • 339 views

These new fossils are intriguing as hell

by zacharoo in Lawn Chair Anthropology

Some big changes here at Lawnchair Anthropology. I just successfully defended my dissertation (Mandibular Growth in Australopithecus robustus, more info on that to come), and moved to Kazakhstan to begin my new job in the School of Humanities and Social Sciences at Nazarbayev University. I landed in Astana about 22 hours ago, so I should be asleep, battling (or succumbing to) jetlag, but some friends have pointed me to newly published early Homo fossils from Kenya, dating to between 1.9-1.6........ Read more »

Meave G. Leakey, Fred Spoor, M. Christopher Dean, Craig S. Feibel, Susan C. Antón, Christopher Kiarie, & Louise N. Leakey. (2012) New fossils from Koobi Fora in northern Kenya confirm taxonomic diversity in early Homo. Nature, 201-204. DOI: 10.1038/nature11322  

  • May 1, 2012
  • 07:59 AM
  • 358 views

Humans still subject to natural and sensual selection (again)

by zacharoo in Lawn Chair Anthropology

The above headline is nothing new, but something still important to remind people about. (also we say 'sensual' instead of 'sexual selection' to keep this a family place. Crap, I just said 'sexual.') A little over a year ago a popular physicist got in some trouble for saying that humans were impervious to evolution because natural selection was no longer able to act on us smart creatures. Right after the scientist put a big smelly foot in his mouth I explained why this statement was incorrect&nb........ Read more »

Courtiol, A., Pettay, J., Jokela, M., Rotkirch, A., & Lummaa, V. (2012) Natural and sexual selection in a monogamous historical human population. Proceedings of the National Academy of Sciences. DOI: 10.1073/pnas.1118174109  

  • April 27, 2012
  • 10:38 AM
  • 416 views

Climate change works fast

by zacharoo in Lawn Chair Anthropology

A study just came out in Science showing that the water cycle - the process of water being evaporated to the atmosphere, condensed into clouds, and returned to Earth as rain - has sped up dramatically in just the past 50 years (Durack et al. 2012). From news coverage of the research (Kerr 2012), here's a reason why this speed-up sucks and has the potential to suck more:Such a revved-up water cycle would have “a lot of implications for how extreme events would change in a warming climate,........ Read more »

  • March 28, 2012
  • 10:57 PM
  • 387 views

An un-hominid foot in hominid times

by zacharoo in Lawn Chair Anthropology

Though my better sense tells me not to say this, researchers announced in Nature today the discovery of a 3.4 million-year-old foot that doesn't "toe the hominid line." Dammit I regret that already. Anyway, Ethiopian paleoanthropologist Yohannes Haile-Selassie and colleagues have found the foot of a creature whose big toe was oriented away from the rest of the foot and capable of grasping, like all primates (including Ardipithecus ramidus) except hominids. See for yourself:BRT-VP-........ Read more »

Haile-Selassie, Y., Saylor, B., Deino, A., Levin, N., Alene, M., & Latimer, B. (2012) A new hominin foot from Ethiopia shows multiple Pliocene bipedal adaptations. Nature, 483(7391), 565-569. DOI: 10.1038/nature10922  

  • March 27, 2012
  • 11:53 AM
  • 388 views

Avoid the Noid... I mean Noise

by zacharoo in Lawn Chair Anthropology

As alluded to yesterday, my dissertation compares growth in an extinct animal with growth in living humans; this study is necessarily cross-sectional, meaning that it examines individuals at a single point in time. Alternatively, longitudinal data sample individuals from several points in time. So for instance if I constructed a growth curve by measuring the stature of a bunch of people of different ages in just a day, that would be cross-sectional. But if I had the time and wherewithal to ........ Read more »

  • March 13, 2012
  • 11:57 AM
  • 562 views

Osteology everywhere: Pelvis has left the building

by zacharoo in Lawn Chair Anthropology

The vernal awakening has brought rain to Ann Arbor, and right on here on main campus I spotted the rain-splotched silhouette of an articulated human pelvis (left).Check out those short and flaring iliac blades, and the shortness of the ischium. These features are associated with repositioning key muscles for walking and running on two feet, and are very unlike what is seen in the four-legged, suspensory climbing apes.But just how 'human' are these features? The crushed pelvis of Oreopithecus bam........ Read more »

  • February 24, 2012
  • 02:11 AM
  • 412 views

You may have my statistical codes

by zacharoo in Lawn Chair Anthropology

As I've been working on my dissertation, I've had to come up with some new ways to compare (cross-sectional) growth in crappy fossil samples with a larger reference population. I've coded a procedure in the R statistical program that uses resampling to test whether two groups differ in the amount of size change experienced between various different ages (i.e. growth). This code is now available on my website.**And how timely - a commentary in this week's issue of Nature demands th........ Read more »

  • February 22, 2012
  • 07:20 PM
  • 432 views

Osteology Everywhere

by zacharoo in Lawn Chair Anthropology

I saw a humerus bone sticking out of the ground on my walk home today.Just kidding. It was just a stupid tree (left). But it does look a lot like a reversed back-side view of the ASK-VP-3/78 distal humerus of Ardipithecus kadabba (right-most of the right pic; Haile-Selassie 2001). It's like someone blew up and unacceptably interred, exposing only the top of the olecranon fossa (the big pit in the pic on the right, where the roots bifurcate on the tree at left). "ARE YOU A HOMINID ........ Read more »

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