Adaptive antiviral defense mechanisms, in archaea and bacteria, based on DNA repeat arrays called CLUSTERED REGULARLY INTERSPACED SHORT PALINDROMIC REPEATS (CRISPR elements) that function in conjunction with CRISPR-ASSOCIATED PROTEINS (Cas proteins). Several types have been distinguished, including Type I, Type II, and Type III, based on signature motifs of CRISPR-ASSOCIATED PROTEINS.
All of Africa except Northern Africa (AFRICA, NORTHERN) including ANGOLA; BENIN; BOTSWANA; BURKINA FASO; CABO VERDE; CAMEROON; CENTRAL AFRICAN REPUBLIC; CHAD; CONGO; COTE D'IVOIRE; DEMOCRATIC REPUBLIC OF THE CONGO; DJIBOUTI; EQUATORIAL GUINEA; ERITREA; ESWATINI; ETHIOPIA; GABON; GAMBIA; GHANA; GUINEA; GUINEA-BISSAU; KENYA; LESOTHO; LIBERIA; MALAWI; MALI; MAURITANIA; MOZAMBIQUE; NAMIBIA; NIGER; NIGERIA; RWANDA; SAO TOME AND PRINCIPE; SENEGAL; SIERRA LEONE; SOMALIA; SOUTH AFRICA; SOUTH SUDAN; SUDAN; TANZANIA; TOGO; UGANDA; ZAMBIA; and ZIMBABWE.