The cafe was busy, so it took Nathan a while to be served. Bright clinking sounds of spoons-on-cups cut through the cafe’s hubbub. Staking out a couch for them in front of the glorious stained-glass windows, Elizabeth stared at her favourite feature in the tableau, the multicoloured Celtic cross. Unlike most of the windows in the Library’s foyer, the cross wasn’t part of a pair. Elizabeth had always wondered why. Now that she worked here, she really should find out.
‘So, tell me, how’d everything go this week?’ asked Nathan, placing Elizabeth’s cappuccino in front of her. ‘Judy? The Phantom? And, most importantly, what happened at uni last weekend?’
Elizabeth’s relief must have shown on her face as she sipped her coffee and returned it to its saucer.
‘Good, by the looks of things?’ Nathan prompted.
‘Yes, very good. No Phantom…Judy hasn’t left me on my own for too long…and everything worked out at uni. I’m going back in the morning.’
‘Excellent. What exactly will you be doing?’
Elizabeth’s smile broadened. She knew Nathan wouldn’t know what dental non-metrics were, but trusted that he would be curious. ‘Taking the first set of data for a dental non-metric assessment of the skeletal remains,’ she said.
‘Exciting stuff,’ he chuckled, ‘and yet I feel singularly unenlightened.’
‘Really? Would you like me to explain?’ Elizabeth teased.
‘Yes please, miss.’
They both laughed.
‘Alrighty then. Dental non-metrics. First, how much genetics have you studied? Where should I start?’
‘I did the basics in high school. I stopped taking science after Year Ten to focus on history and geography.’
‘I’ll start from the beginning then. So, like most sciencey things, genetics is both straightforward and complex at the same time. We’ll go with the straightforward version, but imagine caveats like “in general”, “broadly speaking”, and “for the most part”, in front of everything I say. Yes?’
‘Yes, ma’am!’
Elizabeth laughed. ‘You’re okay with the idea that each human being inherits half their DNA from their mother and half from their father?’
‘Yes.’
‘You’re also familiar with the idea that some genes are dominant, and some are recessive, or submissive?’
‘Yes.’
‘As an example, you can have Rhesus positive blood, as in “O positive”, or Rhesus negative blood, as in “O negative”. ’
‘Yep,’ Nathan said. ‘And, if I remember correctly, as positive is dominant, you can have either two positives, or one positive and one negative version of the gene, and you always get positive blood, but you need two negative genes to get negative. Correct?’
‘Right! You must have been paying attention in Year Ten.’
‘I even remember the names of the guys who first discovered the double helix, Crick and Watson.’
Elizabeth sucked air through her teeth.
‘No?’
‘It was a woman actually, Rosalind Franklin, who first photographed the double helix. The detail of what happened afterwards is a bit murky, but it appears her photographs were stolen and shown to Crick and Watson without her permission. She didn’t receive any credit for her own discovery. I’m certain if she had been a man, she wouldn’t have been treated so shabbily.’
‘Oh.’ Nathan looked genuinely upset. ‘I’m sorry. I feel ashamed of being a man every time I hear about something like that.’
‘No, I should probably say sorry, I reacted too strongly.’ Elizabeth tried to brighten the mood with a little joke. ‘I call it being Franklined – when someone else claims credit for your work, but they probably wouldn’t have if you were a man.’
‘Franklined. I’ll remember that, although it’s unlikely to happen to me. All right, recap: we inherit genes from both parents, and some copies of the same gene are dominant over others.’
‘Yes. And genes then code all the different parts of our bodies. They determine the size and shape of our bones, the size and shape and colour of our fleshy bits, and a lot of our personality. This is where it gets interesting. The way some genes manifest in our bodies is affected by other factors, like sex or environment.’
‘What do you mean, environment?’
‘Everything, really. Temperature, the amount of sunlight we get, everything that goes into our bodies as food or water or air. The way many of our genes, dominant or not, are expressed in our bodies can also be affected by the way people around us behave, and our relationships with them.’
‘Really?’
‘Uh-huh. So even if your genes say you will be tall but you are starved as a child, you’ll end up short.’
Nathan nodded.
‘But, there are some genes to do with brain development that can be switched on or off depending on upbringing.’
‘And that can affect your personality?’
‘Yep. Apparently, the only aspect of human personality that has no discernible genetic component is sense of humour. Everything else, all your preferences and behaviours, are determined to some degree by your genes.’
‘Ah, I think I understand,’ Nathan said, not sounding sure.
‘Okay. Imagine you and your identical twin are born with genes that predispose you to a particular mental illness, say, depression.’
‘All right.’
‘You are split up at birth, and raised in two totally different families.’
‘Okay.’
‘Now, lots of different stressors can precipitate depression. Let’s say your adoptive family is very relaxed, you grow up in a supportive, healthy, understanding environment, and through your whole life nothing major goes wrong.’
‘Nice for some!’
‘Yes, it would be. Okay, so even though you’re predisposed to depression nothing ever happens to tip you over the edge and you avoid it your whole life. Your poor twin, however, was adopted by a family of anxious, depressed, stress bunnies who scream at each other on a regular basis. The stress of this environment triggers their first depressive episode at age ten, and thereafter they suffer from depression to a greater or lesser extent for the rest of their life.’
‘That’s awful.’ Nathan paused. ‘It does explain a lot of what happens to people who grow up in bad situations, though, doesn’t it?’
Elizabeth nodded grimly. ‘Some of it, yes.’
‘Not good. You mentioned sex as well?’
‘Yes. The expression of some genes is affected by the levels of male and female hormones in your body. You’ve probably seen brothers and sisters who look very alike, where the brother is basically a bigger, craggier version of the sister?’
‘Yes, Chloe and me for one.’ Nathan wasn’t exactly testosterone-ridden, so his sister Chloe must be quite petite.
‘Everything about the male sibling is a bit bigger: his bones, his muscles, even his teeth.’
‘Okay.’
‘Now, the size of someone’s bones and teeth can be measured with a tape measure…so long, so wide, et cetera. That’s called metrics. Here’s what I’m looking at, though…the shape. That’s non-metrics: things that can’t be assessed with a tape measure. For example, you can have a non-metric description of a cranium, that’s the head, or the post-cranial parts of a skeleton, that’s everything below the head…and you can have dental non-metrics.’
‘Aha! It all becomes clear, sort of.’
‘So, why are dental non-metrics so important, I hear you ask?’
‘Why are dental non-metrics so important?’ Nathan chortled.
‘Because your sex and the environment have almost no impact on the shape of your teeth. The shape of your teeth is about ninety-five percent determined by your genes. So, the shape of your teeth gives us a kind of blurry blueprint of your teeth-shaping genes.’
‘Okay, I think I’m keeping up.’
‘Good! We’re almost there. So, we can take that fuzzy blueprint of the genes for your tooth shape, and the
blueprints of everyone in your family, or your community, and come up with a kind of average shape for the group. By comparing different groups of people, whether they’re families or communities, we can work out how close or distant they are from each other, genetically speaking, based on the shape of their teeth. That’s dental non-metrics.’
‘Fascinating! But, please don’t be annoyed with me for asking, why would you go to all the trouble of doing it that way? Why not just do DNA tests?’
‘It’s okay, fair question. Two reasons. When you work on archaeological remains, not all the skeletons are well preserved or young enough to have DNA left. Also, DNA testing is expensive.’
‘That makes sense. But how do you write down the shape? If you can’t measure it, what do you record?’
‘My favourite little plaster casts,’ Elizabeth grinned. ‘The variation in the shapes of human teeth is actually fairly limited. There are only so many different shaped lumps and bumps. So, some clever people at Arizona State University came up with a set of plaster casts that provide examples of most of the variation found in humans. It’s easy enough to record which variation a particular tooth has.’
‘Lumps and bumps?’
‘A good example is what’s called ‘shovelling.’ If you put your tongue behind your upper front teeth, you will probably feel that they are flat. Yes?’
‘Yes.’
‘While mine, because I’m part Chinese, are slightly shovel-shaped. Like this…’ Elizabeth held up a cupped hand.
‘Oh! Weird!’
‘Not to me. Nor to my grandmother, who is fully Chinese and has full shovelling. The plaster-cast system has eight degrees of variation for shovelling, from nought, which is no shovelling, up to seven, which is full shovelling. So to record the degree of shovelling, all you do is write down nought, for someone like you, or seven, for someone like Nainai, my grandmother. Then repeat for all the other dental non-metric traits, and voila – a dental non-metric dataset.’
‘That’s rigorous enough to work?’
‘Has up until now!’
‘Hang on, isn’t that what you did for your PhD?’
‘You have been paying attention.’
‘This all sounds pretty complicated. I imagine you must be good at chess. Any chance you play?’
‘No,’ Elizabeth answered, too firmly. Her mother had been on the way to pick Elizabeth up from a chess tournament the day she died. Elizabeth hadn’t touched a chess piece since.
Nathan looked confused, unsure of what he had said or done wrong.
Unwilling to let such a good conversation end on a sour note, Elizabeth asked Nathan about his paper for the librarian conference. His smile returned.
— —
That evening, Elizabeth unpacked shelves of boxes in the garage to find her Arizona State University Dental Anthropology System. She couldn’t wait to use it again.
At sunrise the next morning, Elizabeth carefully laid the delicate little plaster casts out on the laboratory bench. There they were, side by side, the tiny, beautiful shapes detailing various expressions of winging, shovelling, the metacone, the hypercone, and her personal favourite, Carabelli’s cusp. This last feature was an extra little ridge on the inside of the upper first molar, a trait Elizabeth shared with Taid and Grandmère.
Elizabeth had reviewed her notes on how to apply the system the previous night. As she had used the system on a daily basis for months in London, working on an ancient Egyptian population, she was confident she wouldn’t make any mistakes. Good process required that she record the data on two separate occasions, though, with a decent interval in between, to check she was applying it consistently. Today would be her first session.
Ffwrdd a ni!
She could include the fifteen juveniles and adults in her dataset, the infants having no erupted teeth. It was a small sample size, but valuable. She would start with the youngest group of children and work her way up through the age brackets. An arbitrary approach, but she liked being organised.
Gauging the presence of tiny peaks and troughs, the intricate wrinkles and dips of tooth after tooth, was precise work. The plaster casts captured such fine gradations between one level of expression of a trait to the next that Elizabeth had to handle them gently. She didn’t want to misrecord something simply because a minute piece of plaster had chipped off.
Elizabeth worked with one skull and then another, noting first the upper jaw, or maxillary, traits, then the lower jaw, or mandibular, ones. Even in its raw state, the data seemed to fit well within the Mesoamerican population prior to European invasion: extensive shovelling behind the upper front incisors, well-developed tuberculum dentale – the extra little nodules on the back of some front teeth – and no Carabelli’s cusp.
Again, the dentition of the individuals from Juluwik was remarkably similar, echoing the impression Elizabeth received from their crania. It was as though she were looking at a group of closely related people, perhaps only one or two degrees of separation, instead of distantly related members of a community. Were they a group of highly inbred royals? She had seen that pattern repeatedly when studying ancient Egyptian dynasties.
Elizabeth thought about how she might find more clues to the relationships between the women and children. If they were very closely related, had they also died close to each other in time, or over the course of a few decades or centuries? Perhaps if she reviewed the site files from Juluwik, looking at everything to do with the graves and the grave goods, she might find a lead.
That led to another question: why would females be buried with male grave goods? Given how poorly Juan performed when determining the sex of the adult remains, perhaps he had misinterpreted the grave goods as well?
Packing up her belongings, Elizabeth decided to spend next Saturday reviewing the site files in detail. The answers to her questions had to be somewhere, and the files were as good a place as any to start.
— —
That evening Elizabeth logged on to her computer to check her email. Great news! Alice had the go-ahead to use her funding for the x-rays and DNA tests, and could access an electron scanning microscope. Disappointingly, there were no emails from Luke. That was to be expected, but still, Elizabeth couldn’t help but hope. She sent him another email with further thoughts for his applications.
Her final act before turning in was to review her report to Carl one last time. Certain it was as accurate as it could be, Elizabeth attached it to an email and hit Send. That was it. Finally, her name would appear on a publication.
— —
The following Saturday morning Elizabeth was ensconced in the lab by seven o’clock. She had woken at four o’clock, too excited to sleep, and lay in bed planning her day.
Today she would review all of the site documentation. Then, tonight, she could set part of her mind to analyse the file contents while she finished her application for the tutoring positions, which she had started during the week. She also needed to stay near her computer tonight and tomorrow to help Luke finish his applications. She couldn’t wait to Skype with him. Applying for these jobs was the most positive thing they had done together since she had had to leave Egypt.
With a pile of soft manila folders in front of her, a steaming cup of apple tea beside her, Elizabeth snuggled deeply into her oversized cable-knit jumper and began.
The first documents in the Juluwik files were a set of black-and-white aerial photographs. Elizabeth was not practised at interpreting the outlines of ancient constructions in the grey shades of vegetation, but she thought she could make something out. Maybe.
Next were infrared photos of the same area, which were much clearer. Foundations for huge buildings and avenues stood out clearly. Taken a few hours after sunset, infrared photos picked out the remains of constructions as they cooled at a different rate to the soil around them. They were very useful, but expensive: given that Carl couldn’t afford to remunerate her, how had he paid for infra-red equipment and night-time helicopter flights?
Next were the first photographs of the writing in the cave. Wow! Now that she came to look at it closely, the writing was stunning. Such care had been taken to carve the twenty-five intricate glyphs into the cave wall. Could they really be the first writing in the Americas? Although she hadn’t specialised in epigraphology, Elizabeth knew enough of the development of writing systems in ancient Egypt, India and China to know that an emerging writing system usually started out quite simply. The Olmec inscription looked fairly advanced.
The first photo of the cave’s floor showed extensive disturbance of the soil in one corner: the dog who was trapped in there must have tried to dig its way out. The next file contained multiple images of the cave taken with ground-penetrating radar, showing the location of the grave goods.
Right, here was some of the information she was looking for. Two types of dating – radiocarbon and thermoluminescence – had been carried out on various figurines recovered from the site. They hovered around a date of three thousand, two hundred years ago. That indicated that the skeletal remains were of the same age, but Elizabeth preferred absolute dating methods wherever possible. An over-reliance on relative, written or age-equivalent dating methods could lead to mistakes, so Elizabeth would ask if Alice’s budget could stretch far enough to date the skeletons as well.
Hmmm. All the items that were dated came from other parts of Juluwik, not from the graves in the cave. Hang on, Juan said the ballplayer figurine was three thousand, two hundred years old. Hadn’t it been dated? Elizabeth searched the whole file. No, only ceramic items from other parts of the site had been dated. That was strange, surely one of the first things Carl would have done was date the grave goods? And where were the analyses of the soil from the graves?
Olmec Obituary Page 11