Mark Lasbury

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  • September 2, 2015
  • 08:15 AM
  • 35 views

Don’t Disrespect The Dizygotic

by Mark Lasbury in As Many Exceptions As Rules

Spies try to look boring, but in reality they are much more interesting than the average Joe. So it is with dizygotic twins; monozygotic twins (“identical”) get all the glory, but they’re just a split egg, any female can do it. But dizygotic twins – certain families have more, Nigerian women have more, older women have more, taller women and overweight women have more. Now there’s something that looks boring but must be interesting.... Read more »

Simpson, C., Robertson, D., Al-Musawi, S., Heath, D., McNatty, K., Ritter, L., Mottershead, D., Gilchrist, R., Harrison, C., & Stanton, P. (2014) Aberrant GDF9 Expression and Activation Are Associated With Common Human Ovarian Disorders. The Journal of Clinical Endocrinology , 99(4). DOI: 10.1210/jc.2013-3949  

Palmer, J., Zhao, Z., Hoekstra, C., Hayward, N., Webb, P., Whiteman, D., Martin, N., Boomsma, D., Duffy, D., & Montgomery, G. (2006) Novel Variants in Growth Differentiation Factor 9 in Mothers of Dizygotic Twins. The Journal of Clinical Endocrinology , 91(11), 4713-4716. DOI: 10.1210/jc.2006-0970  

Hoekstra, C., Willemsen, G., van Beijsterveldt, C., Lambalk, C., Montgomery, G., & Boomsma, D. (2010) Body composition, smoking, and spontaneous dizygotic twinning. Fertility and Sterility, 93(3), 885-893. DOI: 10.1016/j.fertnstert.2008.10.012  

Groeneveld, E., Lambers, M., Stakelbeek, M., Mooij, T., van den Belt-Dusebout, A., Heymans, M., Schats, R., Hompes, P., Hoek, A., Burger, C.... (2012) Factors associated with dizygotic twinning after IVF treatment with double embryo transfer. Human Reproduction, 27(10), 2966-2970. DOI: 10.1093/humrep/des258  

  • August 26, 2015
  • 08:45 AM
  • 74 views

Twins That Share More Than Clothes

by Mark Lasbury in As Many Exceptions As Rules

Not every pair of monozygotic twins have the same chromosomes. Mosaic twins can be boy and girl, yet both babies come from a single zygote. The strange part is that the tests we run to prevent IVF problems may actually contribute to mosaic twinning. And have you heard of polar body twins? They’re ½ identical twins!... Read more »

Souter, V., Parisi, M., Nyholt, D., Kapur, R., Henders, A., Opheim, K., Gunther, D., Mitchell, M., Glass, I., & Montgomery, G. (2006) A case of true hermaphroditism reveals an unusual mechanism of twinning. Human Genetics, 121(2), 179-185. DOI: 10.1007/s00439-006-0279-x  

Tachon, G., Lefort, G., Puechberty, J., Schneider, A., Jeandel, C., Boulot, P., Prodhomme, O., Meyer, P., Taviaux, S., Touitou, I.... (2014) Discordant sex in monozygotic XXY/XX twins: a case report. Human Reproduction, 29(12), 2814-2820. DOI: 10.1093/humrep/deu275  

  • August 19, 2015
  • 06:30 AM
  • 115 views

Epigenetics And The Evil Twin

by Mark Lasbury in As Many Exceptions As Rules

Monozygotic twins share 100% of their genes. Does this make them identical? Not by a long shot. Epigenetics is the field of study that looks at how environment can change how something looks or works without changing its genes. Is epigenetics responsible for evil twin syndrome in American television?... Read more »

Spannhoff, A., Kim, Y., Raynal, N., Gharibyan, V., Su, M., Zhou, Y., Li, J., Castellano, S., Sbardella, G., Issa, J.... (2011) Histone deacetylase inhibitor activity in royal jelly might facilitate caste switching in bees. EMBO reports, 12(3), 238-243. DOI: 10.1038/embor.2011.9  

Kahn, H., Graff, M., Stein, A., Zybert, P., McKeague, I., & Lumey, L. (2008) A fingerprint characteristic associated with the early prenatal environment. American Journal of Human Biology, 20(1), 59-65. DOI: 10.1002/ajhb.20672  

Zwijnenburg, P., Meijers-Heijboer, H., & Boomsma, D. (2010) Identical but not the same: The value of discordant monozygotic twins in genetic research. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics. DOI: 10.1002/ajmg.b.31091  

Thacker, D., Gruber, P., Weinberg, P., & Cohen, M. (2009) Heterotaxy Syndrome with Mirror Image Anomalies in Identical Twins. Congenital Heart Disease, 4(1), 50-53. DOI: 10.1111/j.1747-0803.2008.00229.x  

  • August 12, 2015
  • 08:15 AM
  • 131 views

When A Twin Vanishes

by Mark Lasbury in As Many Exceptions As Rules

The things that can happen to twins in the womb before they can be born are bizarre. Some get absorbed by their sibling and some just vanish. Two conjoined twins might grow differently and one may becomes a parasite – one boy just had a second face coming out of his chest that could smile, blink and cry. Even scarier - many of you are harboring a twin right now.... Read more »

Navaei AA, Habibi Z, Moradi E, & Nejat F. (2015) Parasitic rachipagus twins; report of two cases. Child's nervous system : ChNS : official journal of the International Society for Pediatric Neurosurgery, 31(6), 1001-3. PMID: 25715843  

Daga, B., Chaudhary, V., Ingle, A., Dhamangaokar, V., Jadhav, D., & Kulkarni, P. (2009) Double fetus-in-fetu: CT scan diagnosis in an adult. Indian Journal of Radiology and Imaging, 19(3), 216. DOI: 10.4103/0971-3026.54890  

Zahed, L., Oreibi, G., Darwiche, N., & Mitri, F. (2004) Potential trisomy 21 misdiagnosis by amniocentesis due to a resorbed twin. Prenatal Diagnosis, 24(12), 1013-1013. DOI: 10.1002/pd.918  

Lakhoo, K., Ringo, Y., Sillo, T., & Drake, D. (2012) Parasitic twin within spina bifida. African Journal of Paediatric Surgery, 9(3), 240. DOI: 10.4103/0189-6725.104728  

  • August 5, 2015
  • 08:10 AM
  • 141 views

One Egg, Two People, A Bunch of Reasons

by Mark Lasbury in As Many Exceptions As Rules

Man has been cloning himself for thousands of years. They’re called monozygotic twins. But how it occurs naturally is still a mystery. Identical twinning isn’t common, but is increased by in vitro fertilization techniques. Maybe this will give clues as to why one embryo splits. And if it doesn’t split completely – conjoined twins.... Read more »

  • July 29, 2015
  • 10:30 AM
  • 166 views

It’s 11 PM, Do You Know Where Your Organs Are?

by Mark Lasbury in As Many Exceptions As Rules

It’s a miracle that a human body ever works like it’s supposed to. So many things can go wrong and there’s so few ways for things to be right. Ever hear of a defect called situs ambiguus? It’s a big problem. And what’s more, when something like transposition of the great arteries occurs, it’s only a second defect that keeps the patients alive.... Read more »

  • July 22, 2015
  • 08:10 AM
  • 132 views

Organs Don’t Always Follow The Plan

by Mark Lasbury in As Many Exceptions As Rules

Do you know where your heart is located? Do you know exactly? Maybe not. It isn’t where most people think it is, and in some people it’s on the opposite side. Situs inversus is a mirror imaging of internal organs, and it’s caused by a faulty motorboat rotor on the embryo.... Read more »

  • July 15, 2015
  • 08:25 AM
  • 176 views

Ovaries March To A Different Drummer

by Mark Lasbury in As Many Exceptions As Rules

A woman’s right ovary kicks her left ovary’s behind. It puts out more hormones and more pregnancies result from right-sided ovulations than from left-sided ovulations. And there’s none of this right-left stuff you’ve been taught, the ovaries don’t have to take turns ovulating every other month. In fact, a study showed that the best chance for pregnancy is if the ovulation pattern is left-left-right over a three-cycle interval. ... Read more »

Zheng, X., O’Connor, J., Huchzermeyer, F., Wang, X., Wang, Y., Wang, M., & Zhou, Z. (2013) Preservation of ovarian follicles reveals early evolution of avian reproductive behaviour. Nature, 495(7442), 507-511. DOI: 10.1038/nature11985  

  • July 8, 2015
  • 08:30 AM
  • 181 views

What the Heck Are Those Doing There?

by Mark Lasbury in As Many Exceptions As Rules

The neuroendocrine system has lots of exceptions, and this includes the male testes. Just why are they housed outside the main body cavities where they are vulnerable to all sorts of dangers, including your siblings’ kicks? You may think you know, but you probably have only part of the answer. Why is one bigger than the other and why do some animals only have one? ... Read more »

Bogaert, A. (1997) Genital asymmetry in men. Human Reproduction, 12(1), 68-72. DOI: 10.1093/humrep/12.1.68  

  • July 1, 2015
  • 08:30 AM
  • 175 views

Thinking Asymmetrically About Hormones

by Mark Lasbury in As Many Exceptions As Rules

Your endocrine glands are stimulated or suppressed by hormones. They in turn dump hormones into the blood. Blood goes everywhere equally. So why is your left adrenal gland bigger than your right? And why is the size difference larger in domesticated foxes as opposed to wild foxes? For that matter, why is the size of the right lobe of your thyroid gland depend on which hand you use to write!?... Read more »

Trut LN, Prasolova LA, Kharlamova AV, & Plyusnina IZ. (2002) Directional left-sided asymmetry of adrenals in experimentally domesticated animals. Bulletin of experimental biology and medicine, 133(5), 506-9. PMID: 12420075  

Hojaij, F., Vanderlei, F., Plopper, C., Rodrigues, C., Jácomo, A., Cernea, C., Oliveira, L., Marchi, L., & Brandão, L. (2011) Parathyroid gland anatomical distribution and relation to anthropometric and demographic parameters: a cadaveric study. Anatomical Science International, 86(4), 204-212. DOI: 10.1007/s12565-011-0111-0  

  • June 24, 2015
  • 08:00 AM
  • 207 views

The CPU In Your Head

by Mark Lasbury in As Many Exceptions As Rules

It’s hard to believe, but part of your brain – the part that controls your body systems – actually comes from your mouth! What’s more, that same part of the brain talks to cells in your lungs that can smell what you breathe in and may have something to do with Sudden Infant Death Syndrome.... Read more »

Gu, X., Karp, P., Brody, S., Pierce, R., Welsh, M., Holtzman, M., & Ben-Shahar, Y. (2014) Chemosensory Functions for Pulmonary Neuroendocrine Cells. American Journal of Respiratory Cell and Molecular Biology, 50(3), 637-646. DOI: 10.1165/rcmb.2013-0199OC  

  • June 19, 2015
  • 06:30 PM
  • 238 views

Fibonacci Numbers And Odd Lungs

by Mark Lasbury in As Many Exceptions As Rules

Most people think that because they have a pair of lungs, they must be symmetrical – but they’re far from it. The Fibonacci sequence has a lot to do with structural asymmetries in the lungs. On the other hand, some animals have only one lung, some have three lungs, and some have no lungs at all.... Read more »

Wilkinson M, Kok PJ, Ahmed F, & Gower DJ. (2014) Caecilita Wake . Zootaxa, 383-8. PMID: 24871732  

Bickford, D., Iskandar, D., & Barlian, A. (2008) A lungless frog discovered on Borneo. Current Biology, 18(9). DOI: 10.1016/j.cub.2008.03.010  

Goldberger AL, West BJ, Dresselhaus T, & Bhargava V. (1985) Bronchial asymmetry and Fibonacci scaling. Experientia, 41(12), 1537-8. PMID: 4076397  

  • June 10, 2015
  • 08:00 AM
  • 281 views

Everybody Is Just A Little Twisted

by Mark Lasbury in As Many Exceptions As Rules

You may have your head on straight, but your brain is still twisted. Everyone’s is. The symmetry of the brain is not absolute and the two halves are shaped differently, this results in your brain torquing (not twerking) inside your skull. The reasons are many, but one is gender: boy brains and girl brains really are different!... Read more »

Maller, J., Anderson, R., Thomson, R., Rosenfeld, J., Daskalakis, Z., & Fitzgerald, P. (2015) Occipital bending (Yakovlevian torque) in bipolar depression. Psychiatry Research: Neuroimaging, 231(1), 8-14. DOI: 10.1016/j.pscychresns.2014.11.008  

Maller, J., Thomson, R., Rosenfeld, J., Anderson, R., Daskalakis, Z., & Fitzgerald, P. (2014) Occipital bending in depression. Brain, 137(6), 1830-1837. DOI: 10.1093/brain/awu072  

Mock, J., Zadina, J., Corey, D., Cohen, J., Lemen, L., & Foundas, A. (2012) Atypical Brain Torque in Boys With Developmental Stuttering. Developmental Neuropsychology, 37(5), 434-452. DOI: 10.1080/87565641.2012.661816  

Witelson, S., Kigar, D., & Harvey, T. (1999) The exceptional brain of Albert Einstein. The Lancet, 353(9170), 2149-2153. DOI: 10.1016/S0140-6736(98)10327-6  

  • June 3, 2015
  • 08:15 AM
  • 267 views

Left-Handers Have Prettier Brains

by Mark Lasbury in As Many Exceptions As Rules

Take a quick look at the human brain and it seems very symmetrical. Well, it’s not. Which hand you use can help determine just how symmetrical your brain actually is, and for some people that’s really important – they were born with only half a brain!... Read more »

Rogers, L., Zucca, P., & Vallortigara, G. (2004) Advantages of having a lateralized brain. Proceedings of the Royal Society B: Biological Sciences, 271(Suppl_6). DOI: 10.1098/rsbl.2004.0200  

Muckli, L., Naumer, M., & Singer, W. (2009) Bilateral visual field maps in a patient with only one hemisphere. Proceedings of the National Academy of Sciences, 106(31), 13034-13039. DOI: 10.1073/pnas.0809688106  

  • May 27, 2015
  • 08:00 AM
  • 236 views

Hermit Houses And Fiddler Claws

by Mark Lasbury in As Many Exceptions As Rules

Fiddler crabs are an evolutionary marvel. Their major claw is huge, it plays a role in mate selection, but not just in the way you’d think.
Some species are right-clawed and some can have the major claw on either side, but if they lose one and grow it back, the major claw might switch sides! The new major claw isn’t as good for fighting, so he fakes being strong and tries to win without fighting.
... Read more »

Backwell, P., Matsumasa, M., Double, M., Roberts, A., Murai, M., Keogh, J., & Jennions, M. (2007) What are the consequences of being left-clawed in a predominantly right-clawed fiddler crab?. Proceedings of the Royal Society B: Biological Sciences, 274(1626), 2723-2729. DOI: 10.1098/rspb.2007.0666  

  • May 20, 2015
  • 08:00 AM
  • 319 views

The Ugly Butterfly Gets The Girl

by Mark Lasbury in As Many Exceptions As Rules

A current theory is that humans (and other animals) perceive symmetry as beauty and is desirable in a mate. Symmetric bodies and faces are correlated with strength, overall health, facial beauty, and dancing ability, but also with extramarital affairs. On the other hand, on butterfly thrives on ugliness. Asymmetric wings actually help males fly better during sexual competitions and gives them a reproductive advantage.... Read more »

Little, A., Paukner, A., Woodward, R., & Suomi, S. (2012) Facial asymmetry is negatively related to condition in female macaque monkeys. Behavioral Ecology and Sociobiology, 66(9), 1311-1318. DOI: 10.1007/s00265-012-1386-4  

Fink, B., Weege, B., Manning, J., & Trivers, R. (2014) Body symmetry and physical strength in human males. American Journal of Human Biology, 26(5), 697-700. DOI: 10.1002/ajhb.22584  

Thomas F, Doyon J, Elguero E, Dujardin JP, Brodeur J, Roucher C, Robert V, Missé D, Raymond M, & Trape JF. (2015) Plasmodium infections and fluctuating asymmetry among children and teenagers from Senegal. Infection, genetics and evolution : journal of molecular epidemiology and evolutionary genetics in infectious diseases, 97-101. PMID: 25725158  

  • May 13, 2015
  • 08:00 AM
  • 281 views

Half Male, Half Female, Completely Weird

by Mark Lasbury in As Many Exceptions As Rules

It’s tough being a guy. I imagine it’s just as tough being a girl. What if you were exactly half of each? Bilateral gynandromrophs are rare animals that are exactly one half of each sex. They have occurred in insects, crustaceans, spiders, and birds. We know how some come about, but the birds are giving scientists a heck of a time.... Read more »

Renfree, M., Chew, K., & Shaw, G. (2014) Hormone-Independent Pathways of Sexual Differentiation. Sexual Development, 8(5), 327-336. DOI: 10.1159/000358447  

Dumanski, J., Rasi, C., Lonn, M., Davies, H., Ingelsson, M., Giedraitis, V., Lannfelt, L., Magnusson, P., Lindgren, C., Morris, A.... (2014) Smoking is associated with mosaic loss of chromosome Y. Science, 347(6217), 81-83. DOI: 10.1126/science.1262092  

Zhao, D., McBride, D., Nandi, S., McQueen, H., McGrew, M., Hocking, P., Lewis, P., Sang, H., & Clinton, M. (2010) Somatic sex identity is cell autonomous in the chicken. Nature, 464(7286), 237-242. DOI: 10.1038/nature08852  

  • May 6, 2015
  • 08:00 AM
  • 339 views

Plants Aren’t Just Male Or Female

by Mark Lasbury in As Many Exceptions As Rules

It’s hard enough to believe that flowering plants have different sexes, but how about plants that have three sexes? One trioecious plant varies it sex ratio depending on how much water is around, while another only shows three sexes when it lives near a particular bat. But most amazing, man made the papaya into a three-sex plant. Your tropical fruit salad is made with a hermaphrodite.... Read more »

VanBuren R, Zeng F, Chen C, Zhang J, Wai CM, Han J, Aryal R, Gschwend AR, Wang J, Na JK.... (2015) Origin and domestication of papaya Yh chromosome. Genome research, 25(4), 524-33. PMID: 25762551  

  • April 29, 2015
  • 08:00 AM
  • 288 views

The Flower Child Must Be Confused

by Mark Lasbury in As Many Exceptions As Rules

Very few animal species have true hermaphrodites, but over 90% of flowering plants are bisexual. Even though the rest are exceptions, they aren’t all the same type of exception. Some plants are male and some are female all the time, but some change sex every morning they flower. And maple tress can decide to be male or female for a whole year and then change their mind for next year.... Read more »

Spigler, R., & Ashman, T. (2011) Gynodioecy to dioecy: are we there yet?. Annals of Botany, 109(3), 531-543. DOI: 10.1093/aob/mcr170  

Matallana, G., Wendt, T., Araujo, D., & Scarano, F. (2005) High abundance of dioecious plants in a tropical coastal vegetation. American Journal of Botany, 92(9), 1513-1519. DOI: 10.3732/ajb.92.9.1513  

Renner SS, Beenken L, Grimm GW, Kocyan A, & Ricklefs RE. (2007) The evolution of dioecy, heterodichogamy, and labile sex expression in Acer. Evolution; international journal of organic evolution, 61(11), 2701-19. PMID: 17894810  

  • April 22, 2015
  • 08:00 AM
  • 272 views

Boys Will Be Boys… And Then Girls

by Mark Lasbury in As Many Exceptions As Rules

Country teenagers still make summer money detasseling corn, but do you know why it has to be done? This is part of the interesting story of the many breeding systems in plants. Self-pollination is a bad idea, so some plants go to the trouble of switching sexes several times in a week just to avoid it!... Read more »

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