title: Estimating cell depth from somatic mutations.
abstract: The depth of a cell of a multicellular organism is the number of cell divisions it underwent since the zygote, and knowing this basic cell property would help address fundamental problems in several areas of biology. At present, the depths of the vast majority of human and mouse cell types are unknown. Here, we show a method for estimating the depth of a cell by analyzing somatic mutations in its microsatellites, and provide to our knowledge for the first time reliable depth estimates for several cells types in mice. According to our estimates, the average depth of oocytes is 29, consistent with previous estimates. The average depth of B cells ranges from 34 to 79, linearly related to the mouse age, suggesting a rate of one cell division per day. In contrast, various types of adult stem cells underwent on average fewer cell divisions, supporting the notion that adult stem cells are relatively quiescent. Our method for depth estimation opens a window for revealing tissue turnover rates in animals, including humans, which has important implications for our knowledge of the body under physiological and pathological conditions.
authors.affiliation: Department of Biological Chemistry, Weizmann Institute of Science, Rehovot, Israel.
authors.forename: Adam
authors.initials: A
authors.lastname: Wasserstrom
authors.forename: Dan
authors.initials: D
authors.lastname: Frumkin
authors.forename: Rivka
authors.initials: R
authors.lastname: Adar
authors.forename: Shalev
authors.initials: S
authors.lastname: Itzkovitz
authors.forename: Tomer
authors.initials: T
authors.lastname: Stern
authors.forename: Shai
authors.initials: S
authors.lastname: Kaplan
authors.forename: Gabi
authors.initials: G
authors.lastname: Shefer
authors.forename: Irena
authors.initials: I
authors.lastname: Shur
authors.forename: Lior
authors.initials: L
authors.lastname: Zangi
authors.forename: Yitzhak
authors.initials: Y
authors.lastname: Reizel
authors.forename: Alon
authors.initials: A
authors.lastname: Harmelin
authors.forename: Yuval
authors.initials: Y
authors.lastname: Dor
authors.forename: Nava
authors.initials: N
authors.lastname: Dekel
authors.forename: Yair
authors.initials: Y
authors.lastname: Reisner
authors.forename: Dafna
authors.initials: D
authors.lastname: Benayahu
authors.forename: Eldad
authors.initials: E
authors.lastname: Tzahor
authors.forename: Eran
authors.initials: E
authors.lastname: Segal
authors.forename: Ehud
authors.initials: E
authors.lastname: Shapiro
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology* / Q000502:physiology*; D001483:Base Sequence; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000235:genetics*; D004252:DNA Mutational Analysis / Q000379:methods*; D006822:Hybrid Cells / Q000502:physiology*; D051379:Mice; D018895:Microsatellite Repeats / Q000235:genetics*; D008969:Molecular Sequence Data; D017422:Sequence Analysis, DNA / Q000379:methods*