胚胎有自我修復染色體基因機制，啟動異常細胞自我凋亡

囊胚期胚胎染色體檢查顯示，僅有23%染色體完全正常
有3/4胚胎染色體有不同程度之鑲嵌化異常mosaicism
胚胎有自我修復染色體基因之複雜機制，啟動異常染色體之胚胎細胞自我凋亡，保留染色體正常之細胞

http://humrep.oxfordjournals.org/content/18/12/2565.full

Table II.

Chromosomal classification of human preimplantation embryos grown in vitro until the blastocyst stage

Embryo status	n
No. analysed	84
Chromosomally abnormal in origin	0 (0)
Chromosomally normal in origin	84 (100)
Chromosomally normal at blastocyst stage	19 (22.6)
Chromosomally abnormal at blastocyst stage	65 (77.4)
Simple mosaic	10 (11.9)
Complex mosaic	27 (32.1)
Chaotic	14 (16.7)
Unexplained	14 (16.7)

Values in parentheses are percentages.

Chromosomal features of the embryos were determined using criteria described in Materials and methods.

Table V.

Cell number of inner cell mass (ICM) and trophectoderm (TE) respectively, and of the whole blastocyst analysable for FISH (n = 84)

Blastocyst populationa	n	ICM	TE	Whole blastocyst
Total	84	35.0 ± 3.1	44.4 ± 3.1	79.2 ± 4.5
Normal	19	28.2 ± 5.3	40.1 ± 5.6	68.3 ± 8.6
Abnormal	65	35.6 ± 3.6	43.1 ± 3.4	78.7 ± 5.0
Simple mosaic	10	33.5 ± 7.3	38.9 ± 6.2	72.4 ± 8.7
Complex mosaic	27	34.0 ± 6.0	47.3 ± 6.9	81.2 ± 9.6
Chaotic	14	46.3 ± 9.9	45.6 ± 5.4	91.9 ± 11.3
Unexplained	14	29.1 ± 4.2	37.1 ± 4.8	66.2 ± 5.4

^aChromosomal features of the embryos were determined using criteria described in Materials and methods.

Normal = chromosomally normal at blastocyst stage; Abnormal = chromosomally abnormal at the blastocyst stage.

Data are presented as mean (± SEM) number of cells.