{'fraction_non_alphanumeric': 0.018826135105204873, 'fraction_numerical': 0.013289036544850499, 'mean_word_length': 5.550724637681159, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Mechanisms that generate human immunoglobulin diversity operate from the 8th week of gestation in fetal liver

The repertoire of immunoglobulin expressed very early in human development was approached by cloning and sequencing 55 rearranged and 11 germ‐line VH transcripts, after amplification by polymerase chain reaction of cDNA libraries derived from two fetal livers at 8 and 13 weeks of gestation. All families with the exception of VH2, were expressed as soon as 8 weeks, with preferential usage of certain germ‐line genes. Very few somatic mutations, randomly localized, were identified. By contrast, in a series of clones derived from the same VDJ rearrangement using the VH6 family, extensive mutations had taken place, mostly accumulated in the third complementarity‐determining region (CDR3) suggesting that the specialized enzymatic machinery was at hand very early during human development.