DNA, chromatin and genome numbers

The DNA double helix is 2 nm wide. 10 base pairs (= one turn of the helix) have a linear length of 3.4 nm.

The following table gives the size of folded DNA pieces according to different models.  Some values would make no sense (e.g. length of 10 base pairs in mitotic chromosomes) and are therefore omitted from the table.

linear 10 nm fiber 30 nm fiber model 130 nm chromonema fiber model metaphase chromosomes
compaction ratio 1:1 1:6 1:40 at least 1:160 (maybe 1:1000) ~ 1:10 000
width 2 nm 10 nm 30 nm 130 nm 600 nm per chromatid






10 base pairs 3.4 nm



100 bp 34 nm



1 kb 340 nm 57 nm


10 kb 3,4 µm 570 nm 85 nm 21 nm   (if 1:160)
100 kb 34 µm 5.7 µm 850 nm 212 nm  (if 1:160)
1 Mb 340 µm = 0.34 mm 57 µm 8.5 µm 2.125 µm (if 1:160) 34 nm
1 Gb 340 mm = 0.34 m


34 µm
3 Gb (haploid human genome) 1 m


100 µm =  0.1 mm
 
 

Volume of human genome packed in a cube (no proteins, naked DNA): 6.9 µm³

A nucleosome core particle (without H1) binds 146 base pairs. The linker DNA between nucleosomes is 0-80 base pairs. On average there is one nucleosome per 200 bp. The size of the nucleosome is 10-11 nm wide, 6 nm high. It leads to a DNA-package ratio of about 1:6

An IgG antibody is roughly (!) 10 nm long. The weight is about 150 kDa (this value comes from here) . More on antibodies here or here .
 

Haploid genome sizes

size  haploid chromosome count
E. coli 4.7 Mb 1
S. cerevisiae 14 Mb 16
C. elegans 100 Mb 11 or 12
D. melanogaster 170 Mb 4
Gallus domesticus (chicken) 1.2 Gb 39
H. sapiens, Mus musculus, Xenopus laevis 3 Gb 23, 20 and 18
individual human chromosomes,  each 50 - 250 Mb

If you have more numbers that would fit on this page, please let me know. e-mail: steffen@dietzellab.de
Data for this page were taken from a number of leading text books and for the chromonema fiber from Belmont and Bruce, J. Cell Biol. 127:287-302, 1994 .
Last change: 5.Okt.2001
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