Currently, there are only 400 sequences reported for B.1.640 variant. In a similar vein to the recent split of B.1.1.529 (Omicron, 奥密克戎) into two sister sublineages it appears B.1.640 may also have a similar issue with a major group constating of the vast majority of sequences and a small outgroup which appears related but has a very different set of mutations (EPI_ISL_7181977; EPI_ISL_7156959; EPI_ISL_7156955; EPI_ISL_6315910; EPI_ISL_5926666) and includes sequences from France and England, indicating some degree of spread. (by Tom Peacock )

Defining mutations (mutations not shared between both groups shown in bold):

Major lineage: B.1.640.1
刺突蛋白突变 Spike - P9L, E96Q, Δ136-144, R190S*, I210T, R346S, N394S, Y449N, F490R, N501Y, D614G, P681H, T859N, D936H

非S突变 Non-spike - NSP2 – P129L, E272G; NSP3 – L1301F, A1537S; NSP4 – S386F, R401H, T492I; NSP6 – V149A; NSP12 – P323L; T32I, Q57H; M – I82T; ORF8 – Q27*STOP; N- D22Y, T205I, E378Q; S2m deletion

Minor lineage: B.1.640.2
刺突蛋白突变 Spike - P9L, E96Q, Δ136-144, R190S, D215H, R346S, N394S, Y449N, E484K, F490S, N501Y, D614G, P681H, T859N, D1139H

非S突变 Non-spike - NSP2 – P129L; NSP4 – D459N; NSP6 – Δ106-108, T181I; NSP12 – P323L; NSP13 – V371A; NSP14 – P46S, V437F; ORF3a – T32I, Q57H; M – I82S; ORF8 – Q27*STOP; N – D22Y, T205I

以上转自：https://github.com/cov-lineages/pango-designation/issues/362

New ‘IHU’ B.1.640.2 Covid-19 Coronavirus Variant Detected In France 

It’s also been temporarily dubbed the “variant IHU” because a team from the Méditerranée Infection University Hospital Institute (IHU，法国马赛地中海感染研究所) in Marseilles, France , was the first to report the variant in a pre-print uploaded to MedRxiv on December 29.

参考文献：
Emergence in Southern France of a new SARS-CoV-2 variant of probably Cameroonian origin harbouring both substitutions N501Y and E484K in the spike protein. Philippe Colson, Jérémy Delerce, Emilie Burel, Jordan Dahan, Agnès Jouffret, Florence Fenollar, Nouara Yahi, Jacques Fantini, Bernard La Scola, Didier Raoult

Doi: https://doi.org/10.1101/2021.12.24.21268174