有些句子不太理解？求解

hyde

For example,only zygotes and blastomeres of early morulas retain the ability to give rise to all embryonic and extraembryonic
  X5 N- G+ i& P: y9 vtissues (Kelly 1977), and are therefore called ‘‘totipotent,’’ while cells of the inner cell mass (ICM) of the blastocyst can give rise to all embryonic but not all extraembryonic tissues, and are hence called ‘‘pluripotent.’’ Cells residing in adult tissues, such as adult stem cells, can only give rise to cell types within their lineage and are called either ‘‘multipotent’’ or ‘‘unipotent,’’ depending on the number of developmental options they have.. y) c2 o( N1 C  l# _2 m7 [
上述句子关于全能性，多能的描述有点乱了？？？？
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3 U1 Q# G: M! B3 e5 eHowever,most cloned animals exhibit subtle to severe phenotypic and gene expression abnormalities, suggesting that SCNT
% N$ ?* l7 [2 U3 Iresults in faulty epigenetic reprogramming.
0 \  G: u7 a- M" O) J8 h+ sThe major conclusion from these and subsequent findings was that development imposes reversible epigenetic rather
( ^: p/ q  s5 [$ v4 l5 jthan irreversible genetic changes on the genome during cellular differentiation.   e) S* ^9 _# |5 D/ M+ k
如何理解epigenetic？exhibit subtle to severe phenotypic？

hyde

另外求助http://www.stemcell8.cn/thread-28662-1-1.html

idealgas

epigenetic？exhibit subtle to severe phenotypic？. Q% Q8 E6 j1 r1 Y- J. c5 l
本文来自干细胞之家  - 中国干细胞研究员的交流论坛，http://www.stemcell8.cn，详情请看：http://www.stemcell8.cn/thread-28877-1-1.html
% O& {- \0 C! i. {6 v; @5 Mepigenetic 是“表观遗传学的”就是编码基因的DNA序列不发生变化，而只是组蛋白或者碱基的修饰发生变化，比如甲基化、乙酰化等，而对遗传发生影响。
6 u* s* r) Z: Cexhibit subtle to severe phenotypic and gene expression abnormalities" Q- `5 {( R9 _$ T' G
这才是完整的一个词语，是说转基因的动物表现出轻微的或者严重的表型和基因表达的异常。

hyde

回复 3# idealgas 9 Z5 E1 m8 ^* |) @5 C+ T& ?

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( s0 a5 C% J# s    连出处都知道，哥您也太牛了吧！！
" ^6 @8 Y% j& w% m非常感谢哦………………

hyde

epigenetics:表观遗传学又称“拟遗传学”、“表遗传学”、“外遗传学”以及“后遗传学”，是一门生物学学科，研究在没有细胞核DNA序列改变的情况时，基因功能的可逆的、可遗传的改变。这些改变包括DNA的修饰(如甲基化修饰)、组蛋白的各种修饰等。也指生物发育过程中包含的程序的研究。在这两种情况下，研究的对象都包括在DNA序列中未包含的基因调控信息如何传递到（细胞或生物体的）下一代这个问题。在西方文字中epigenetics即指在DNA包含的遗传信息以外附加的（希腊文前缀epi-）。" `' I, O& v1 H0 I+ S* W. Q: I
　　表观遗传学是20世纪80年代逐渐兴起的一门学科，是在研究与经典孟德尔遗传学遗传法则不相符的许多生命现象过程中逐步发展起来的。' C' A$ M* {& j  |8 H; t7 D0 l3 S
　　表观遗传现象包括DNA甲基化、RNA干扰、组蛋白修饰等。与经典遗传学以研究基因序列影响生物学功能为核心相比，表观遗传学主要研究这些“表观遗传现象”的建立和维持的机制。

hyde

人烟稀少呀…………

hyde

很多问题还是自己来解决吧：
5 |  c9 Q0 z2 P! S- [Totipotent stem cells： can differentiate into embryonic and extraembryonic cell types.Such cells can construct a complete, viable,organism. These cells are produced from the fusion of an egg and sperm cell. Cells produced by the1 D$ R# o, T- ^# T" u$ V+ V- P
first few divisions of the fertilized egg are also totipotent.
  S( [; J1 L* f+ w- m. wPluripotent stem cells：are the descendants of totipotent cells and can differentiate into nearly all cells,i.e. cells derived from any of the three germ layers.- U9 v! E+ a! @! u
Multipotent stem cells： can differentiate into a number of cells, but only those of a closely related family of cells.
7 m. B/ T' e( G. Y! xOligopotent stem cells： can differentiate into only a few cells, such as lymphoid or myeloid stem cells.; `5 C7 f( a2 B0 r, F) @
Unipotent cells ：can produce only one cell type, their own,but have the property of selfrenewal which distinguishes them from non-stem cells (e.g. muscle stem cells).

starlancer

哪里描述乱了？建议lz多看相关文献。合子是目前公认的唯一的全能性细胞，这是没有错的。关于那句话，可以翻译成：大多数克隆的动物都表现出轻微或者严重的表型和基因表达异常，这表明体细胞核移植导致了错误的表观遗传重编程。( G/ e( X7 a! r# Q
意思是：核移植虽然能够给予一个完整的基因型，但由于表观遗传学上的错误导致了基因表达的异常，从而引起了表型的异常。