Editing Chromosome (section)

=== Human chromosomes ===
Chromosomes in humans can be divided into two types: [[autosome]]s (body chromosome(s)) and allosome ([[sex chromosome]](s)). Certain genetic traits are linked to a person's sex and are passed on through the sex chromosomes. The autosomes contain the rest of the genetic hereditary information. All act in the same way during cell division. Human cells have 23 pairs of chromosomes (22 pairs of autosomes and one pair of sex chromosomes), giving a total of 46 per cell. In addition to these, human cells have many hundreds of copies of the [[mitochondrial genome]]. [[DNA sequencing|Sequencing]] of the [[human genome]] has provided a great deal of information about each of the chromosomes. Below is a table compiling statistics for the chromosomes, based on the [[Sanger Institute]]'s human genome information in the [[Vertebrate and Genome Annotation Project|Vertebrate Genome Annotation (VEGA) database]].<ref>[http://vega.sanger.ac.uk/Homo_sapiens/index.html Vega.sanger.ad.uk], all data in this table was derived from this database, 11 November 2008.</ref> Number of genes is an estimate, as it is in part based on [[gene prediction]]s. Total chromosome length is an estimate as well, based on the estimated size of unsequenced [[heterochromatin]] regions.

{| class="wikitable sortable" style="text-align:right"
|+
|-
! Chromosome !! [[Gene]]s<ref>{{Cite web|url=http://apr2013.archive.ensembl.org/Homo_sapiens/Location/Chromosome?r=1:1-1000000|title=Ensembl genome browser 71: Homo sapiens – Chromosome summary – Chromosome 1: 1–1,000,000|website=apr2013.archive.ensembl.org|access-date=11 April 2016}}</ref> !! Total [[nucleobase|base pairs]] !! % of bases 
|-
| [[Chromosome 1|1]] ||2000|| 247,199,719 ||8.0
|-
| [[Chromosome 2|2]] ||1300|| 242,751,149 ||7.9
|-
| [[Chromosome 3|3]] ||1000|| 199,446,827 ||6.5
|-
| [[Chromosome 4|4]] ||1000|| 191,263,063 ||6.2
|-
| [[Chromosome 5|5]] ||900|| 180,837,866 ||5.9
|-
| [[Chromosome 6|6]] ||1000|| 170,896,993 ||5.5
|-
| [[Chromosome 7|7]] ||900|| 158,821,424 ||5.2
|-
| [[Chromosome 8|8]] ||700|| 146,274,826 ||4.7
|-
| [[Chromosome 9|9]] ||800|| 140,442,298 ||4.6
|-
| [[Chromosome 10|10]] ||700|| 135,374,737 ||4.4
|-
| [[Chromosome 11|11]] ||1300|| 134,452,384 ||4.4
|-
| [[Chromosome 12|12]] ||1100|| 132,289,534 ||4.3
|-
| [[Chromosome 13|13]] ||300|| 114,127,980 ||3.7
|-
| [[Chromosome 14|14]] ||800|| 106,360,585 ||3.5
|-
| [[Chromosome 15|15]] ||600|| 100,338,915 ||3.3
|-
| [[Chromosome 16|16]] ||800|| 88,822,254 ||2.9
|-
| [[Chromosome 17|17]] ||1200|| 78,654,742 ||2.6
|-
| [[Chromosome 18|18]] ||200|| 76,117,153 ||2.5
|-
| [[Chromosome 19|19]] ||1500|| 63,806,651 ||2.1
|-
| [[Chromosome 20|20]] ||500|| 62,435,965 ||2.0
|-
| [[Chromosome 21|21]] ||200|| 46,944,323 ||1.5
|-
| [[Chromosome 22|22]] ||500|| 49,528,953 ||1.6
|-
| [[X chromosome|X (sex chromosome)]] ||800|| 154,913,754 ||5.0
|-
| [[Y chromosome|Y (sex chromosome)]] ||200<ref name="NCBI-1998">{{Cite book| title = Genes and Disease| chapter = Chromosome Map| publisher = National Center for Biotechnology Information| location = Bethesda, Maryland|url = https://www.ncbi.nlm.nih.gov/books/NBK22266/#A296| year = 1998}}</ref>|| 57,741,652 ||1.9
|- class="sortbottom"
! Total ||style="text-align:right"| 21,000 ||style="text-align:right"| 3,079,843,747 ||style="text-align:right"| 100.0 
|}

Based on the micrographic characteristics of size, position of the [[centromere]] and sometimes the presence of a [[chromosomal satellite]], the human chromosomes are classified into the following groups:<ref>The colors of each row match those of the karyogram (see Karyotype section)</ref><ref>{{cite journal|author1=Erwinsyah, R.|author2=Riandi|author3=Nurjhani, M.|year=2017|title=Relevance of human chromosome analysis activities against mutation concept in genetics course. IOP Conference Series.|journal=Materials Science and Engineering|doi=10.1088/1757-899x/180/1/012285|s2cid=90739754 |doi-access=free}}</ref>
{|class=wikitable
! Group
! Chromosomes
! Features
|- style="background:lavenderblush"
| '''A'''
| 1–3
| Large, metacentric or submetacentric
|- style="background:honeydew"
| '''B'''
| 4–5
| Large, submetacentric
|- style="background:lightyellow"
| '''C'''
| 6–12, X
| Medium-sized, submetacentric
|- style="background:linen"
| '''D'''
| 13–15
| Medium-sized, acrocentric, with [[Satellite chromosome|satellite]]
|- style="background:lightcyan"
| '''E'''
| 16–18
| Small, metacentric or submetacentric
|- style="background:lavender"
| '''F'''
| 19–20
| Very small, metacentric
|- style="background:lavenderblush"
| '''G'''
| 21–22, Y
| Very small, acrocentric (and 21, 22 with [[Satellite chromosome|satellite]])
|}