<html>
<head>
<meta content="text/html; charset=windows-1252"
http-equiv="Content-Type">
</head>
<body bgcolor="#FFFFFF" text="#000000">
On 2016-04-07 17:29, spike wrote:<br>
<blockquote cite="mid:010201d190ea$b5d42020$217c6060$@att.net"
type="cite">
<meta http-equiv="Content-Type" content="text/html;
charset=windows-1252">
<meta name="Generator" content="Microsoft Word 15 (filtered
medium)">
<style><!--
/* Font Definitions */
@font-face
{font-family:"Cambria Math";
panose-1:2 4 5 3 5 4 6 3 2 4;}
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Consolas;
panose-1:2 11 6 9 2 2 4 3 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:11.0pt;
font-family:"Calibri",sans-serif;
color:black;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:#0563C1;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:#954F72;
text-decoration:underline;}
pre
{mso-style-priority:99;
mso-style-link:"HTML Preformatted Char";
margin:0in;
margin-bottom:.0001pt;
font-size:10.0pt;
font-family:"Courier New";
color:black;}
p.msonormal0, li.msonormal0, div.msonormal0
{mso-style-name:msonormal;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:12.0pt;
font-family:"Times New Roman",serif;
color:black;}
span.EmailStyle18
{mso-style-type:personal;
font-family:"Calibri",sans-serif;
color:windowtext;}
span.HTMLPreformattedChar
{mso-style-name:"HTML Preformatted Char";
mso-style-priority:99;
mso-style-link:"HTML Preformatted";
font-family:"Consolas",serif;
color:black;}
span.EmailStyle21
{mso-style-type:personal-reply;
font-family:"Calibri",sans-serif;
color:windowtext;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext="edit" spidmax="1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext="edit">
<o:idmap v:ext="edit" data="1" />
</o:shapelayout></xml><![endif]-->
<div class="WordSection1">
<p class="MsoNormal"><span style="color:windowtext"><o:p> </o:p></span></p>
<pre><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">Cool, so this leads into my next comment. We saw that it was 60 years between the first marginal chess program to the orders-of-magnitude more impressive champion AlphaGo. We know that cheap technology exists in which a prole can get her DNA file. If a number of siblings have that DNA file, they can figure out the genome of their parents, and if several cousins compare their genomes, they can piece together the genomes of their mutual grandparents, second cousins their great grandparents and so on.<o:p></o:p></span></pre>
<pre><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></pre>
<pre><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext">If we could synthesize a DNA strand by some means using a DNA file, we could perhaps use it to clone someone who lived a long time ago, given sufficient numbers of their descendants have their DNA files.<o:p></o:p></span></pre>
<pre wrap=""><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:windowtext"><o:p> </o:p></span></pre>
</div>
</blockquote>
<br>
Remember that each offspring gets 50% of the genome (lets ignore X
and Y chromosomes). So if you have a sibling, you can reconstruct
about 75% of either of your parents. If you have two, 87.5%, and so
on. To get all 3 billion base pairs right you need 31 siblings<br>
<br>
Going back one generation means you have 25% of (say) grandfather.
So now you need not just a bunch of siblings to build dad's genome
(50% of grandfather), but you need to reconstruct more uncles and
aunts (about 31 of them) using 31 children each. This gets tricky
fast, if your family does not breed like rabbits.<br>
<br>
Accepting a bit less fidelity (say 90%) just requires two-three
siblings for a parent, and two-three reconstructed uncles (about 6
or 7 starting people) for grandfather. But for the generation before
that you need around 16 people, then 39, then 97... And in fact, 90%
fidelity going back four generatons is just 65% fidelity.<br>
<br>
The challenge is that each time we reproduce, half of the genome is
discarded. Yes, we get a lovely replacement half from our partner,
but information is lost. If things go well it is the less important
information that is lost. <br>
<br>
<br>
<pre class="moz-signature" cols="72">--
Anders Sandberg
Future of Humanity Institute
Oxford Martin School
Oxford University</pre>
</body>
</html>