<article xmlns:ali="http://www.niso.org/schemas/ali/1.0/">
  <front>
    <article-meta>
      <title-group>
        <article-title>Lineal admixture time: an interdisciplinary definition</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <contrib-id contrib-id-type="orcid">https://orcid.org/0000-0002-5014-4809</contrib-id>
          <name>
            <surname>Ellerman</surname>
            <given-names>E. Castedo</given-names>
          </name>
          <email>castedo@castedo.com</email>
        </contrib>
      </contrib-group>
      <permissions>
        <copyright-statement>© 2023, Ellerman et al</copyright-statement>
        <license>
          <ali:license_ref content-type="ccbylicense">https://creativecommons.org/licenses/by/4.0/</ali:license_ref>
          <license-p>This document is distributed under a Creative Commons Attribution 4.0 International license.</license-p>
        </license>
      </permissions>
      <abstract>
        <p><bold>STAGE:</bold> DISCUSSION DOCUMENT</p>
        <p><bold>OBJECTIVES:</bold></p>
        <p>
          <list list-type="bullet">
            <list-item>
              <p>Define <italic>lineal admixture time</italic>.</p>
            </list-item>
            <list-item>
              <p>Invite discussion and feedback, especially regarding questions at the end of
              this document.</p>
            </list-item>
            <list-item>
              <p>Facilitate the discovery of mathematical tools, using this definition, that
              are useful to downstream empirical research.</p>
            </list-item>
          </list>
        </p>
        <p><bold>SIGNIFICANCE:</bold>
This definition is interpretable within empirical research without assuming
particular mathematical models of demographic or genetic processes.</p>
        <p><bold>DOWNSTREAM RESEARCH:</bold>
The estimation of the timing and extent of interbreeding between previously
separated populations.</p>
      </abstract>
    </article-meta>
  </front>
  <body>
    <sec id="background">
      <title>Background</title>
      <p>The genealogies of a population reflect population events of the
 past.</p>
    </sec>
    <sec id="definition-of-lineal-admixture-time">
      <title>Definition of lineal admixture time</title>
      <p>We define <italic>lineal admixture time</italic> per lineage. This measure in time duration
   depends on two reference time points:</p>
      <list list-type="order">
        <list-item>
          <p>a past time horizon when all ancestors are members of separate non-admixed
          subpopulations, and</p>
        </list-item>
        <list-item>
          <p>an observation time, such as the present.</p>
        </list-item>
      </list>
      <p>Given a lineage, the <bold>lineal admixture time</bold> is defined as:</p>
      <p><italic>the amount of time since fertilization of the first admixed individual in the
     lineage</italic>.</p>
    </sec>
  </body>
</article>
