1
00:00:03,710 --> 00:00:02,090
they tear themselves in half each half

2
00:00:05,210 --> 00:00:03,720
regenerates the missing piece and now

3
00:00:06,889 --> 00:00:05,220
you've got two that's how they reproduce

4
00:00:09,470 --> 00:00:06,899
so if you're going to do that what you

5
00:00:11,330 --> 00:00:09,480
end up avoiding is weissman's barrier

6
00:00:12,770 --> 00:00:11,340
this idea that when we get mutations in

7
00:00:14,990 --> 00:00:12,780
our body our children don't inherit

8
00:00:17,090 --> 00:00:15,000
those mutations right so this means that

9
00:00:19,310 --> 00:00:17,100
any mutation that doesn't kill the stem

10
00:00:21,230 --> 00:00:19,320
cell in the body gets Amplified as that

11
00:00:24,050 --> 00:00:21,240
cell contributes to regrowing the worm

12
00:00:25,429 --> 00:00:24,060
so every as a result of this for for 400

13
00:00:27,589 --> 00:00:25,439
million years these planaria have

14
00:00:29,810 --> 00:00:27,599
accumulated mutations their genomes are

15
00:00:31,849 --> 00:00:29,820
an incredible mess their cells are

16
00:00:33,290 --> 00:00:31,859
basically mixoploid that meaning meaning

17
00:00:34,370 --> 00:00:33,300
they're like a tumor every cell has a

18
00:00:36,170 --> 00:00:34,380
different number of chromosomes

19
00:00:38,450 --> 00:00:36,180
potentially they're just they just look

20
00:00:40,610 --> 00:00:38,460
look you know it just looks horrible as

21
00:00:43,310 --> 00:00:40,620
an end result you've got an animal that

22
00:00:46,250 --> 00:00:43,320
is Immortal incredibly good at