https://www.pnas.org/content/early/2020/07/21/2002655117

Skip to main content

  * Submit
  * About
      + Editorial Board
      + PNAS Staff
      + FAQ
      + Accessibility Statement
      + Rights and Permissions
      + Site Map
  * Contact
  * Journal Club
  * Subscribe
      + Subscription Rates
      + Subscriptions FAQ
      + Open Access
      + Recommend PNAS to Your Librarian

  * Log in
  * My Cart

Main menu

  * Home
  * Articles
      + Current
      + Latest Articles
      + Special Features
      + Colloquia
      + Collected Articles
      + PNAS Classics
      + Archive
  * Front Matter
  * News
      + For the Press
      + Highlights from Latest Articles
      + PNAS in the News
  * Podcasts
  * Authors
      + Information for Authors
      + Editorial and Journal Policies
      + Submission Procedures
      + Fees and Licenses

  * Submit
  * About
      + Editorial Board
      + PNAS Staff
      + FAQ
      + Accessibility Statement
      + Rights and Permissions
      + Site Map
  * Contact
  * Journal Club
  * Subscribe
      + Subscription Rates
      + Subscriptions FAQ
      + Open Access
      + Recommend PNAS to Your Librarian

User menu

  * Log in
  * My Cart

Search

Search for this keyword 
[                                                            ]
Search 
  * Advanced search

Home
Home
Search for this keyword 
[                                                            ]
Search 
Advanced Search

  * Home
  * Articles
      + Current
      + Latest Articles
      + Special Features
      + Colloquia
      + Collected Articles
      + PNAS Classics
      + Archive
  * Front Matter
  * News
      + For the Press
      + Highlights from Latest Articles
      + PNAS in the News
  * Podcasts
  * Authors
      + Information for Authors
      + Editorial and Journal Policies
      + Submission Procedures
      + Fees and Licenses

New Research In

Physical Sciences

Featured Portals

  * Physics
  * Chemistry
  * Sustainability Science

Articles by Topic

  * Applied Mathematics
  * Applied Physical Sciences
  * Astronomy
  * Computer Sciences
  * Earth, Atmospheric, and Planetary Sciences
  * Engineering
  * Environmental Sciences
  * Mathematics
  * Statistics

Social Sciences

Featured Portals

  * Anthropology
  * Sustainability Science

Articles by Topic

  * Economic Sciences
  * Environmental Sciences
  * Political Sciences
  * Psychological and Cognitive Sciences
  * Social Sciences

Biological Sciences

Featured Portals

  * Sustainability Science

Articles by Topic

  * Agricultural Sciences
  * Anthropology
  * Applied Biological Sciences
  * Biochemistry
  * Biophysics and Computational Biology
  * Cell Biology
  * Developmental Biology
  * Ecology
  * Environmental Sciences
  * Evolution
  * Genetics
  * Immunology and Inflammation
  * Medical Sciences
  * Microbiology
  * Neuroscience
  * Pharmacology
  * Physiology
  * Plant Biology
  * Population Biology
  * Psychological and Cognitive Sciences
  * Sustainability Science
  * Systems Biology

Page Not Found

The requested page "content/early/2020/07/21/2002655117" could not be
found.

Site Logo
Powered by HighWire

  * Submit Manuscript
  * Twitter
  * Facebook
  * RSS Feeds
  * Email Alerts

Articles

  * Current Issue
  * Latest Articles
  * Archive

PNAS Portals

  * Classics
  * Front Matter
  * Teaching Resources
  * Anthropology
  * Chemistry
  * Physics
  * Sustainability Science

Information

  * Authors
  * Editorial Board
  * Reviewers
  * Press
  * Site Map
  * PNAS Updates

[logo-nas-w]

Feedback    Privacy/Legal

Copyright (c) 2020 National Academy of Sciences. Online ISSN 1091-6490