New genetic variants found to influence likelihood of being a morning person

In a new study published today in Nature Communications, 23andMe researchers identified 15 genetic variants associated with being a morning person, including four genetic 11032015_morningness_brandUpdate-1variants never before connected to sleep cycles, and associations like BMI and depression.

“Some circadian rhythm genes we identified have been studied in model organisms, but much less so in humans,” said David Hinds, Ph.D, a Principal Scientist and Statistical Geneticist at 23andMe, who was a co-author on the paper. “We also identified new genes that have not previously been associated with sleep behavior.”

Among the genetic variants in this study, researchers found seven in or near genes already known to play a biological role in circadian rhythms. Four other variants identified are in or near genes that could plausibly be related to circadian rhythm, and the remaining four variants are more of a mystery in the role they play in human sleep cycles.

Analysing the phenotypic data, the researchers also looked at associations between being a morning person and other conditions such as body mass index, insomnia, depression and sleep duration. They found that a morning person is much less likely to have insomnia, less likely to require eight hours of sleep and less likely to suffer from depression than individuals who reported being “night owls.” Taking into account of the effect of age and sex, morning persons are also more likely to have lower BMI, according to the research. The researchers also found that morning persons were less likely to be on the extreme ends of body mass index, meaning they were less likely to be obese as well as less likely to be underweight.

While this does not imply a causation, some of these associations may warrant a deeper dive into the biology. For instance among the new genetic associations found, were several in the FTO gene, which is associated with obesity.

Circadian rhythms are sleep and wake cycles in a 24-hour day. The cycle is triggered by changes in light stimulation. While scientists have long known that one’s genetics can can influence their circadian rhythm, they have yet to piece together the full picture. But understanding why someone is more likely to be a morning person or a “night owl” continues to perplex researchers. By learning more, researchers may be able to better understand certain health conditions that are associated with those differences,  such as depression, obesity, and insomnia.

23andMe’s genome wide association study looked at data from more than 89,000 customers who consented to research and answered questions about their sleep cycles. Using imputation — statistical methods to infer unobserved genotypes — the researchers were able to look across a total of approximately eight million genetic variants giving them a much more robust picture of the genetic influence on sleep cycles. On the eve of publication of 23andMe’s paper, a team at the University of Exeter Medical School in the UK completed a similar study. The researchers there used data from 119,000 individuals in the UK Biobank study, and coordinating with 23andMe’s researchers they were able to replicate 13 of the 16 variants they found associated with being a morning person or “morningness” in that data, including finding variants in genes associated with BMI and circadian rhythms. A preprint of the teams paper, which is in review for publication, is posted here.

Although not part of the research in this paper, 23andMe scientists looked at this data in another way, specifically how “morningness” distributes itself geographically in the United States. Looking at customers in the US who consented to research, our scientists looked at the proportion of morning people by state using random sub-sampling.

The map, below, shows clustering along time zones — especially among the states in the mountain time zone — Colorado, New Mexico, Wyoming, and Montana. And, according to 23andMe scientist Kasia Bryc who did the analysis, some of the states with the highest proportion of morning people also tend to have older populations.   But there are many anomalies, making it difficult to draw conclusions. At the same time the map illustrates that as with most traits, it’s not just genetics that plays a role.

What do you think explains this distribution? 01152016_morningMap_social

The paper appears in the journal PLoS Genetics.






  • Tim Moors

    People migrate to/from places where the effect of the time zone on sunlight matches/mismatches their body clock, e.g. compare this distribution to the distribution of “days with reasonable sunrise time” at http://andywoodruff.com/blog/where-to-hate-daylight-saving-time-and-where-to-love-it/

    • 23blog

      Thanks Tim. This is great, especially the map.

  • Sean O’Connell

    I believe there may be more to it than just being a morning person. If left to myself I will not sleep in a 24 hour cycle and only fit in with it for convenience. My son who makes a living online and is not tied to a timetable for his work actually regularly goes round the clock sleeping probably 9 hours but then staying up 17 or 18 hours before going back to bed. I discovered when taking watches whilst sailing that it suited me perfectly. I don’t suffer from jet lag – I just fit my sleeping in appropriately. Shift work when I did it was no problem. The main reason I am not a morning person when on a 24 hour cycle is that I am tired due to inevitably having gone to bed late.I don’t suffer from insomnia, I am never depressed in the clinical sense. I would like to be lighter and keep fit to promote this but apparently my BMI is reasonably good for my age (66).

  • Hi, how there I’m Yusuf from Bangladesh actually I’m so specialist it’s my job by the way I read your article and knowing what is the Nature Communications it’s helped my job so thank you.

  • 23blog

    Clearly there are other factors involved related to geography, population age and ethnicity in each of these regions. I think the point of looking at geography is to show that environmental factors — time zones perhaps — also play a role in the differences.

  • Humayun

    i make my living online. so many times i go to bed after 18/20 hours or sometime for 1/2 days and it is ok for me.

  • Some great article change people mind

  • KW

    Is there also a mountain correlation? You have the Rockies on the left, and I recall New Hampshire also being mountainous.

    Is it possible to redo the map by county? That might make it easier to filter out the time zone correlation to see if there is a terrain correlation; being on the wrong side of a mountain would seem to have an effect similar to being on the wrong side of a time zone line. You can compare with average elevation (or elevation of county seat, to simplify it), and also compare with calculated slope ratio of the county.

    As for the difference between east and west coast (Appalachian vs Rockies) that could be exposure; the east tends to be moist, while the west tends to be dry, resulting in a vegetation difference. For this, you could compare average morning precipitation or average morning humidity. Washington state shows low percentage, and I recall the state has temperate rainforest and that Seattle tends to have a lot of precipitation.

    Another possibility is to check average morning light levels at ground level, if there is a good source of information for that.

    • 23blog

      KW,
      We do not have county level data, but that would be interesting.

      • KW

        Can you fake it by looking up the county for 23andme kit shipping zip codes (or simply map by zip code itself)? You’ll get some junk data (maybe less if you drop those with multiple kits), but it might be good enough to see if there seems to be something worth following up. I would think zip code is probably sufficiently anonymous to allow it to be included with study data.

        • Robert Sterbal

          Indeed, you might have to drop zip codes with fewer than 3-5 data points.

          I’m going through the same exact question with my 650 person alumni database, some interested in additional perspectives.

  • joanooo

    definite New genetic variants found to influence likelihood of being a morning person
    February 2, 2016 By 23andMe under 23andMe Research
    In a new study published today in Nature Communications, 23andMe researchers identified 15 genetic variants associated with being a morning person, including four genetic 11032015_morningness_brandUpdate-1variants never before connected to sleep cycles, and associations like BMI and depression.

    “Some circadian rhythm genes we identified have been studied in model organisms, but much less so in humans,” said David Hinds, Ph.D, a Principal Scientist and Statistical Geneticist at 23andMe, who was a co-author on the paper. “We also identified new genes that have not previously been associated with sleep behavior.”

    Among the genetic variants in this study, researchers found seven in or near genes already known to play a biological role in circadian rhythms. Four other variants identified are in or near genes that could plausibly be related to circadian rhythm, and the remaining four variants are more of a mystery in the role they play in human sleep cycles.

    Analysing the phenotypic data, the researchers also looked at associations between being a morning person and other conditions such as body mass index, insomnia, depression and sleep duration. They found that a morning person is much less likely to have insomnia, less likely to require eight hours of sleep and less likely to suffer from depression than individuals who reported being “night owls.” Taking into account of the effect of age and sex, morning persons are also more likely to have lower BMI, according to the research. The researchers also found that morning persons were less likely to be on the extreme ends of body mass index, meaning they were less likely to be obese as well as less likely to be underweight.

    While this does not imply a causation, some of these associations may warrant a deeper dive into the biology. For instance among the new genetic associations found, were several in the FTO gene, which is associated with obesity.Circadian rhythms are sleep and wake cycles in a 24-hour day. The cycle is triggered by changes in light stimulation. While scientists have long known that one’s genetics can can influence their circadian rhythm, they have yet to piece together the full picture. But understanding why someone is more likely to be a morning person or a “night owl” continues to perplex researchers. By learning more, researchers may be able to better understand certain health conditions that are associated with those differences, such as depression, obesity, and insomnia.

    23andMe’s genome wide association study looked at data from more than 89,000 customers who consented to research and answered questions about their sleep cycles. Using imputation – statistical methods to infer unobserved genotypes – the researchers were able to look across a total of approximately eight million genetic variants giving them a much more robust picture of the genetic influence on sleep cycles.

    On the eve of publication of 23andMe’s paper, a team at the University of Exeter Medical School in the UK completed a similar study. The researchers there used data from 119,000 individuals in the UK Biobank study, and coordinating with 23andMe’s researchers they were able to replicate 13 of the 16 variants they found associated with being a morning person or “morningness” in that data, including finding variants in genes associated with BMI and circadian rhythms. A preprint of the teams paper, which is in review for publication, is posted here.

    Although not part of the research in this paper, 23andMe scientists looked at this data in another way, specifically how “morningness” distributes itself geographically in the United States. Looking at customers in the US who consented to research, our scientists looked at the proportion of morning people by state using random sub-sampling.The map, below, shows clustering along time zones – especially among the states in the mountain time zone – Colorado, New Mexico, Wyoming, and Montana.

    And, according to 23andMe scientist Kasia Bryc who did the analysis, some of the states with the highest proportion of morning people also tend to have older populations. But there are many anomalies, making it difficult to draw conclusions. At the same time the map illustrates that as with most traits, it’s not just genetics that plays a role.

    What do you think explains this distribution? 01152016_morningMap_socialThe paper appears in the journal PLoS Genetics.

    Tags: BMI, circadian rhythms, depression, insomnia, morning person, night owl, sleep, sleep cycles

    • Elias Sarkis

      Although a lot of areas are mountainous, from my limited geographic knowledge, all of those areas with early-morning people have a great deal of outdoor activities available. I do not remember if activity level was asked. I wonder if it correlates.

  • doggypoop

    My Relatives were all farmers, so when the sun went down it was bedtime, And They were up before the Sun came up

  • Mary Zapparata

    “They found that a morning person is much less likely to have insomnia, less likely to require eight hours of sleep and less likely to suffer from depression than individuals who reported being “night owls.” Taking into account of the effect of age and sex, morning persons are also more likely to have lower BMI, according to the research. The researchers also found that morning persons were less likely to be on the extreme ends of body mass index, meaning they were less likely to be obese as well as less likely to be underweight”. 23andMe tells me I contributed to this, but none of these findings are true of me.

    • Denise Vincent

      Sure, but genetics aren’t necessarily determinative. Just because you’re carrying a gene, doesn’t mean that gene will be expressed. A lot depends on your pre-natal environment, never mind the environment a person lives in over the course of a life. Also, you may have contributed as part of the Control group, if you had none of the genes that were being researched. We’re only told that we’ve contributed, not how we’ve contributed.

    • Bill Bates

      Same as me, I think. We are controls.

  • Denise Vincent

    I suspect that histamine keeps a lot of us with autoimmune disorders up. Lately I can’t fall asleep before 2 AM, whenever the air pollution is worse than usual. I’m not surprised that depression and weight gain would be associated too, since a bad autoimmune flare can lead to a cytokine storm, which has cognitive effects such as fatigue and depression. I’d like to see the correlations with autoimmune issues too. If anyone likes, you can see the specific genes that were analyzed in Table 1 from the study, and then type in each variant to 23andMe’s Explorer page to see if you carry it: http://journals.plos.org/plosgenetics/article?id=10.1371/journal.pgen.1006125

  • I wonder if New Mexico has a high proportion of “morning people” because a lot of the population works at national labs or on military bases, which start work early. If you’re not a morning person you’re less likely to choose that career and end up in New Mexico. Also, it’s beautiful in the morning here. :)

  • stelz

    I know that climate plays a part, at least for me. I live in Texas where the heat is brutal most of the year and can get more done if I wake up late in the afternoon and go to sleep an hour or two after sunrise. But even when I lived in Massachusetts, I was never a morning person – left to my own devices, I’d sleep in until late mornings, at least.

  • Mary Zapparata

    Hi KW, the map doesn’t help me (I’m in Australia). I haven’t actually checked to see if I have the genes involved, so I should do that sometime.

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