Year: 2022

THE WHY. "The puzzle has two sides: why and how has the somatic part of higher animals come to be mortal, and how is the germ-line kept free of the progressive deterioration in the soma?" http://link.springer.com/chapter/10.1007/978-1-4613-1939-9_15 View in LinkedIn

ALL MOLECULES TURN OVER. "In 1891 August Weismann proposed that the germ plasm is immortal. Yet, the repeated replication and repair of DNA results in molecules that do not contain atoms of the same nucleotides present in the DNA of a founding cell." (L. Haflick, the brilliant contrarian, adopting an overly rigid definition of immortality). https://lnkd.in/esfPTAR View in LinkedIn

ARGUMENTATIVE POSITION. "There is a tenable argument that the germ plasm is not immortal because molecules at the end of a lineage of zygotes are not identical to those in the founding gametes." https://lnkd.in/esfPTAR View in LinkedIn

EXACTING POSITION. "Cells at the leading edge of any long lineage do not have the identical molecular content as existed in the founding cell. Even in non-dividing cells, molecular turnover must occur leading to the conclusion that, like dividing cells, non-dividing cells also are not molecularly identical after the passage of time." (L. Haflick, contrarian). https://lnkd.in/esfPTAR View in LinkedIn

LOSS OF SAMENESS. "Also, different genes are contributed from each parent at every fusion that further contributes to loss of sameness. Finally, given equal distribution at each division, other molecules or atoms present in a founding cell are not likely to be present after the clone has produced a lineage of about fifty population doublings." (L. Haflick, contrarian). https://lnkd.in/esfPTAR View in LinkedIn

APPROXIMATE FIDELITY. "A closer approximation to fidelity is that each zygote in the lineage contains the same genetic information as does its precursors following fertilization. This is dubious because of the occurrence of mutations, one of the few universal properties of life." (L. Haflick, contrarian). https://lnkd.in/esfPTAR View in LinkedIn

CONTRARIAN VIEW. "Thus, August Weismann may have been wrong not only because molecular turnover is inevitable in all cell lineages but because the alleged immortality of the germ plasm takes place only under conditions of periodic genetic recombination. By themselves gametes and the germ plasm are not an immortal lineage." (L. Haflick, contrarian). https://lnkd.in/esfPTAR View in LinkedIn

MAINSTREAM VIEW. "The germ line is the one component of the organism that may aspire to immortality and its development and transmission represent the most important tasks undertaken by a multi-cellular organism." https://lnkd.in/g6Q36vi View in LinkedIn

GENE FUNNEL BETWEEN GENERATIONS. "Germ cells are highly specialized cells that form gametes, and they are the only cells within an organism that contribute genes to offspring." https://lnkd.in/dsBeTUt View in LinkedIn

CELLULAR GATEWAY TO THE FUTURE. "Germline stem cells (GSCs) sustain gamete production, both oogenesis (egg production) and spermatogenesis (sperm production), in many organisms." https://lnkd.in/dsBeTUt View in LinkedIn