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- Karmin, Monika, et al.
(författare)
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A recent bottleneck of Y chromosome diversity coincides with a global change in culture.
- 2015
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Ingår i: Genome Research. - : Cold Spring Harbor Laboratory. - 1088-9051 .- 1549-5469. ; 25:4
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Tidskriftsartikel (refereegranskat)abstract
- It is commonly thought that human genetic diversity in non-African populations was shaped primarily by an out-of-Africa dispersal 50-100 thousand yr ago (kya). Here, we present a study of 456 geographically diverse high-coverage Y chromosome sequences, including 299 newly reported samples. Applying ancient DNA calibration, we date the Y-chromosomal most recent common ancestor (MRCA) in Africa at 254 (95% CI 192-307) kya and detect a cluster of major non-African founder haplogroups in a narrow time interval at 47-52 kya, consistent with a rapid initial colonization model of Eurasia and Oceania after the out-of-Africa bottleneck. In contrast to demographic reconstructions based on mtDNA, we infer a second strong bottleneck in Y-chromosome lineages dating to the last 10 ky. We hypothesize that this bottleneck is caused by cultural changes affecting variance of reproductive success among males.
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| 2. |
- Jefferson, A. L., et al.
(författare)
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The Vanderbilt Memory & Aging Project: Study Design and Baseline Cohort Overview
- 2016
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Ingår i: Journal of Alzheimers Disease. - : IOS Press. - 1387-2877 .- 1875-8908. ; 52:2, s. 539-559
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Tidskriftsartikel (refereegranskat)abstract
- Background: Vascular health factors frequently co-occur with Alzheimer's disease (AD). A better understanding of how systemic vascular and cerebrovascular health intersects with clinical and pathological AD may inform prevention and treatment opportunities. Objective: To establish the Vanderbilt Memory & Aging Project, a case-control longitudinal study investigating vascular health and brain aging, and describe baseline methodology and participant characteristics. Methods: From September 2012 to November 2014, 335 participants age 60-92 were enrolled, including 168 individuals with mild cognitive impairment (MCI, 73 +/- 8 years, 41% female) and 167 age-, sex-, and race-matched cognitively normal controls (NC, 72 +/- 7 years, 41% female). At baseline, participants completed a physical and frailty examination, fasting blood draw, neuropsychological assessment, echocardiogram, cardiac MRI, and brain MRI. A subset underwent 24-hour ambulatory blood pressure monitoring and lumbar puncture for cerebrospinal fluid (CSF) collection. Results: As designed, participant groups were comparable for age (p = 0.31), sex (p = 0.95), and race (p = 0.65). MCI participants had greater Framingham Stroke Risk Profile scores (p = 0.008), systolic blood pressure values (p = 0.008), and history of left ventricular hypertrophy (p = 0.04) than NC participants. As expected, MCI participants performed worse on all neuropsychological measures (p-values <0.001), were more likely to be APOE epsilon 4 carriers (p = 0.02), and had enhanced CSF biomarkers, including lower A beta(42) (p = 0.02), higher total tau (p = 0.004), and higher p-tau (p = 0.02) compared to NC participants. Conclusion: Diverse sources of baseline and longitudinal data will provide rich opportunities to investigate pathways linking vascular and cerebrovascular health, clinical and pathological AD, and neurodegeneration contributing to novel strategies to delay or prevent cognitive decline.
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