腦有邊12對染色體???

唔明你問緊乜？你係講緊人類？

人類除咗生殖細胞（精子同卵子）之外，每個細胞都有２３對（即係４６條）染色體（包括腦細胞），生殖細胞因為要結合成為有２３對染色體嘅受精卵，所以各自只有２３條染色體．

其他生物會唔會係得１２對染色體，就要查下先知啦．

以下係一D關於染色體嘅資料，你自己慢慢睇啦．

The human chromosomes
Human cells have 23 pairs of large linear nuclear chromosomes, giving a total of 46 per cell. In addition to these, human cells have many hundreds of copies of the mitochondrial genome. All of the human chromosomes have been sequenced and a great deal is known about each of them.




Chromosome
Genes
Bases
Determined bases†

1
2968
245,203,898
218,712,898

2
2288
243,315,028
237,043,673

3
2032
199,411,731
193,607,218

4
1297
191,610,523
186,580,523

5
1643
180,967,295
177,524,972

6
1963
170,740,541
166,880,540

7
1443
158,431,299
154,546,299

8
1127
145,908,738
141,694,337

9
1299
134,505,819
115,187,714

10
1440
135,480,874
130,710,865

11
2093
134,978,784
130,709,420

12
1652
133,464,434
129,328,332

13
748
114,151,656
95,511,656

14
1098
105,311,216
87,191,216

15
1122
100,114,055
81,117,055

16
1098
89,995,999
79,890,791

17
1576
81,691,216
77,480,855

18
766
77,753,510
74,534,531

19
1454
63,790,860
55,780,860

20
927
63,644,868
59,424,990

21
303
46,976,537
33,924,742

22
288
49,476,972
34,352,051

X (sex chromosome)
1184
152,634,166
147,686,664

Y (sex chromosome)
231
50,961,097
22,761,097

unplaced various
?
25,263,157
25,062,835

† Human Genome Project goals called for determination of only the euchromatic portion of the genome. Telomeres, centromeres, and other heterochromatic regions have been left undetermined, as have a small number of unclonable gaps.[5]


Number of chromosomes in various organisms

Eukaryotes


Chromosome numbers in some plants


Plant Species
#

Arabidopsis thaliana
10

Rye
14

Maize
20

Einkorn wheat
14

Pollard wheat
28

Bread wheat
42

Wild tobacco[citation needed]
24

Cultivated tobacco
48

Adder's Tongue Fern[1]
1262




Chromosome numbers in some animals


Species
#
Species
#

Common fruit fly
8
Guinea Pig
16

Dove[citation needed]
16
Snail[citation needed]
24

Earthworm[2]
36
Tibetan fox
36

Domestic cat
38
Domestic pig
38

Lab mouse
40
Lab rat
42

Rabbit[citation needed]
44
Syrian hamster
44

Hare[citation needed]
46
Human
46

Gorilla, Chimpanzee
48
Domestic sheep
54

Elephant[citation needed]
56
Cow
60

Donkey
62
Horse
64

Dog[3]
78
Chicken
78

Goldfish
104
Butterflies[citation needed]
380