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Table 1 Molecular genetic differences between humans and chimpanzees

From: Differences between human and chimpanzee genomes and their implications in gene expression, protein functions and biochemical properties of the two species

Human

Chimpanzee

Karyotype

46 chromosomes. Chromosome 2 was formed by fusion of two ancestral chromosomes [9].

48 chromosomes, including chromosomes 2a and 2b [9].

Large pericentric inversions in chromosomes 1 and 18 [10,11,12].

Large pericentric inversions in chromosomes 4, 5, 9, 12, 15–17 [10,11,12].

Two pseudoautosomal regions, PAR2 and PAR3 on Y chromosome [13,14,15].

 

Different amounts of pericentric, paracentric, intercalary and Y type heterochromatin [9].

Deletions, insertions, copy number variations (~ 3% of genomes differences)

Several hundreds of species-specific processed pseudogenes [8, 16].

134 genes increased copy numbers, 6 decreased [17]. SRGAP2 duplicated with the formation of two truncated homologs SRGAP2B and SRGAP2C [18].

37 genes increased copy numbers, 15 – decreased [17].

Deletion of 510 conserved regions. Among them: androgen receptor (AR) enhancer, tumor suppressor GADD45G enhancer, CMAHP exon, etc. [19, 20].

Human-specific mobile elements recombination/insertion-associated deletions: at least 492 Alu-associated deletions(~ 400 kb of excised DNA) [21], at least 73 LINE-associated deletions (~ 450 kb of excised DNA) [22, 23], at least 26 SVA-associated deletions (~ 46 kb of excised DNA) [24].

Deletion of 334 conserved regions [19].

Chimpanzee-specific mobile elements recombination/insertion- associated deletions: at least 663 Alu-associated deletions(~ 771 kb of excised DNA) [25].

Mobile elements

• Alu: ~ 5000 unique copies, AluYa5 и AluYb8 families prevail [8, 26, 27]

• LINE L1: ≥ 2000 of unique insertions [26, 28]

• SVA (SINE-VNTR-Alu): several thousands of specific insertions, two times more active retrotransposition [26, 27]. New family emerged - CpG-SVA or SVAF1 [29, 30].

• HERVs: ~ 140 unique insertions of HERV-K (HML-2) [31,32,33,34]. Several hundred copies of HERV-K (HML-2) К111 and several dozen copies of HERV-K (HML-2) K222 emerged due to recombination in centromeric and pericentromeric regions [35, 36].

• Alu: ~ 1500 unique copies, Alu Y and Yc1 families prevail [8, 26, 27]

• LINE L1: ≥ 2000 of unique insertions [26, 28]

• SVA: several thousands of specific insertions [26, 27]

• HERVs: ~ 45 unique insertions of HERV-K (HML-2) [37, 38]

• Two new families emerged – PtERV1 and PtERV2 (totally around 250 copies) [8, 39]

Single nucleotide alterations (substitutions, insertions, deletions): ~ 1.23% of genomes differences

Protein-coding sequences

• Different repertoires of olfactory receptor genes and pseudogenes, 25% out of ~ 400 active genes are species-specific [40].

• Highly diverged genes relate to immunity and cell recognition. Point mutations inactivated genes of T-cell gamma-receptor TCRGV10, caspase 12, mannose-binding lectin gene MBL1P, etc. [8, 41, 42].

• Species-specific mutations in genes responsible for sialic acids metabolism: ST6GAL1, ST6GALNAC3, ST6GALNAC4, ST8SIA2, HF1. Point mutations in genes SIGLEC11 and SIGLEC12 abrogated their sialic-binding activities [8, 43,44,45,46]

• Substitutions in language-associated gene FOXP2: Thr303Asn and Asn325Ser [43, 44].

• Quickly evolving brain size-related genes MCPH1 and ASPM [46, 47].

• Different repertoires of olfactory receptor genes and pseudogenes, 25% out of ~ 400 active genes are species-specific [40].

• Highly diverged genes relate to immunity and cell recognition [8, 41, 42]

• Species-specific mutations in genes responsible for sialic acids metabolism: ST6GAL1, ST6GALNAC3, ST6GALNAC4, ST8SIA2, HF1 [8]

Non-coding sequences

~  3000 of human accelerated regions: HARs and HACNs [48, 49]. HARS and HACNs are enriched in genes related to DNA interaction, transcriptional regulation and neuronal development [50]. NPAS3 (neuronal PAS domain-containing protein) gene contains 14 HARs. The most rapidly evolving regions HAR1 and HARE5 are located in brain-related genes: HAR1F/HAR1R-overlap and FZD8 [48, 49, 51].

~ 100 of human-specific enhancers activated in nervous tissues (hEANTs) [52]