Category Archives: genetics

Instagram Post – Melanocortin 2 Receptor Accessory Protein 2 (Mrap2) and Mammalian Obesity

Instagram Post

The #protein #mrap2 has a dramatic effect on #weight and #bodyfat, if you’re missing both copies of it. (this is extremely rare, only one documented human case). However, this novel work in mice shows how two individuals with similar #activity levels consuming the same number of #calories can end up at different weights. #science #molecularbiology #nytimes via #sciencemagazine

On The Ecosystem Within (UPDATE)

My last post was concerned with the way mice regulate the set of bacteria which reside in their intestines. Which specific bacteria are present in one’s gut is known to be predictive of obesity, but new research suggests that it isn’t the bacteria themselves that are important so much as the genes that they carry1.

Scientists at Washington University in St. Louis studied the bacteria present in the intestines of pairs of twins (a useful methodology for exploring many kinds of similarities amongst individuals with similar genes) and their mothers, expecting to find that those who were obese would have similar species of gut flora (similarly expecting comparable special cross-sections in those who were not obese). Interestingly, they found that the set of bacteria differed widely, but that the core “bacteriome” (the set of all the genes in all the bacteria in a person’s gut) was highly conserved across the obese (and separately across the non-obese). They further found that related individuals were more likely to harbor the same set of species.

This is not incredibly surprising. After all, the functional utility – in terms of digestive assistance, molecular synthesis, and nitrogen uptake – of these bacteria is defined by their genes. That is to say, bacteria can only be useful to us and our internal environment in that they are in possession of metabolic pathways that we lack. Furthermore, given the massive number of bacterial species, it is unsurprising that one person gets a specific part of the benefits from species A, while another person obtains that benefit from species B. It is a happy surprise to me that this research is progressing at an increasing pace. I hope it continues as such.

1. Turnbaugh PJ, Hamady M, Yatsunenko T, Cantarel BL, Duncan A, Ley RE, Sogin ML, Jones WJ, Roe BA, Affourtit JP, Egholm M, Henrissat B, Heath AC, Knight R, Gordon JI. A core gut microbiome in obese and lean twins. Nature [Epub ahead of print], 2008.

On Art from Science

Copyright © 2005 Hunter O’Reilly

Hunter O’Reilly obtained a Ph.D. in genetics from the University of Wisconsin-Madison and graduated cum laude from the University of California, Berkeley. Her abstractions have been shown internationally including galleries in New York, San Francisco, England, Italy, Japan, the Czech Republic, Indiana and Wisconsin.”

“Observations in the laboratory and the world around her inspire the shapes in her abstract oil paintings. Hunter’s abstract art hints at both organic matter at the highest level (human faces) and at the smallest level (single cells). This section includes many images of artwork.”

“O’Reilly teaches biology and art at Loyola University Chicago. She created a course, Biology Through Art, where students have the opportunity to create innovative artworks in a biology laboratory. Students view microorganisms, use DNA as an artistic medium, create music based on DNA sequence and see anatomy as art. The course culminates in students creating their own biological self-portrait.”

More images here.

On The Genetic Basis of Schizophrenia

“… what a narrow ridge of normality we all inhabit, with the abysses of mania and depression yawning to either side.”1

from reference 2

Schizophrenia is a debilitating condition, chronic in nature, that affects approximately 1 in a hundred people worldwide. Although able to strongly suggest a genetic basis, past research has not been truly successful in determining the hereditary underpinnings of this combined neurological and psychiatric disorder.

from reference 3

Two papers, published in the journal Nature, have pushed this field of research farther than ever before, establishing schizophrenia-relevant chromosomal loci and using larger numbers of patients than in the past, for stronger statistical power2,3. These studies focused on two types of chromosomal abnormalities, single nucleotide polymorphisms (SNPs; changes to single bases) and copy-number variations (CNVs; changes in the number of copies of one or more whole genes). Both studies confirmed previous findings of a CNV locus associated with schizophrenia, and validated each other’s implication of two new CNV loci. Although it is still unclear how such information might be used, this is a cause for enthusiasm regarding the treatment of schizophrenia, and the possibility of determining genetic basis for other psychiatric disorders.

1. Sacks, O. A Summer of Madness. The New York Review of Books, LV(14): 57-61, 2008.

2. Stefansson H, Rujescu D, Cichon S, Pietiläinen OP, Ingason A, Steinberg S, Fossdal R, Sigurdsson E, Sigmundsson T, Buizer-Voskamp JE, Hansen T, Jakobsen KD, Muglia P, Francks C, Matthews PM, Gylfason A, Halldorsson BV, Gudbjartsson D, Thorgeirsson TE, Sigurdsson A, Jonasdottir A, Jonasdottir A, Bjornsson A, Mattiasdottir S, Blondal T, Haraldsson M, Magnusdottir BB, Giegling I, Möller HJ, Hartmann A, Shianna KV, Ge D, Need AC, Crombie C, Fraser G, Walker N, Lonnqvist J, Suvisaari J, Tuulio-Henriksson A, Paunio T, Toulopoulou T, Bramon E, Di Forti M, Murray R, Ruggeri M, Vassos E, Tosato S, Walshe M, Li T, Vasilescu C, Mühleisen TW, Wang AG, Ullum H, Djurovic S, Melle I, Olesen J, Kiemeney LA, Franke B, Sabatti C, Freimer NB, Gulcher JR, Thorsteinsdottir U, Kong A, Andreassen OA, Ophoff RA, Georgi A, Rietschel M, Werge T, Petursson H, Goldstein DB, Nöthen MM, Peltonen L, Collier DA, St Clair D, Stefansson K, Kahn RS, Linszen DH, van Os J, Wiersma D, Bruggeman R, Cahn W, de Haan L, Krabbendam L, Myin-Germeys I; Genetic Risk and Outcome in Psychosis (GROUP). Large recurrent microdeletions associated with schizophrenia. Nature, 455(7210):232-236, 2008.

3. Stone JL, O’Donovan MC, Gurling H, Kirov GK, Blackwood DH, Corvin A, Craddock NJ, Gill M, Hultman CM, Lichtenstein P, McQuillin A, Pato CN, Ruderfer DM, Owen MJ, St Clair D, Sullivan PF, Sklar P, Purcell SM, Stone JL, Ruderfer DM, Korn J, Kirov GK, Macgregor S, McQuillin A, Morris DW, O’Dushlaine CT, Daly MJ, Visscher PM, Holmans PA, O’Donovan MC, Sullivan PF, Sklar P, Purcell SM, Gurling H, Corvin A, Blackwood DH, Craddock NJ, Gill M, Hultman CM, Kirov GK, Lichtenstein P, McQuillin A, O’Donovan MC, Owen MJ, Pato CN, Purcell SM, Scolnick EM, St Clair D, Stone JL, Sullivan PF, Sklar P, O’Donovan MC, Kirov GK, Craddock NJ, Holmans PA, Williams NM, Georgieva L, Nikolov I, Norton N, Williams H, Toncheva D, Milanova V, Owen MJ, Hultman CM, Lichtenstein P, Thelander EF, Sullivan P, Morris DW, O’Dushlaine CT, Kenny E, Waddington JL, Gill M, Corvin A, McQuillin A, Choudhury K, Datta S, Pimm J, Thirumalai S, Puri V, Krasucki R, Lawrence J, Quested D, Bass N, Curtis D, Gurling H, Crombie C, Fraser G, Kwan SL, Walker N, St Clair D, Blackwood DH, Muir WJ, McGhee KA, Pickard B, Malloy P, Maclean AW, Van Beck M, Visscher PM, Macgregor S, Pato MT, Medeiros H, Middleton F, Carvalho C, Morley C, Fanous A, Conti D, Knowles JA, Ferreira CP, Macedo A, Azevedo MH, Pato CN, Stone JL, Ruderfer DM, Korn J, McCarroll SA, Daly M, Purcell SM, Sklar P, Purcell SM, Stone JL, Chambert K, Ruderfer DM, Korn J, McCarroll SA, Gates C, Daly MJ, Scolnick EM, Sklar P. Rare chromosomal deletions and duplications increase risk of schizophrenia. Nature, 455(7210):237-241, 2008