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Mullers Ratchet

All articles tagged with #mullers ratchet

science16 days ago

Mammals Cloned Across 58 Generations Collapse, Study Finds

A 20-year experiment cloning over 1,200 mice across 58 generations shows that deleterious genetic mutations accumulate in cloned lineages, with the 58th generation dying shortly after birth. Initial generations appeared healthy, but the line ultimately collapsed, confirming that mammalian cloning cannot sustain long-term viability and that sexual reproduction is essential for species survival; researchers call for advances in nuclear transfer techniques.

Cloning's mutational cliff: line ends after 58 generations
science17 days ago

Cloning's mutational cliff: line ends after 58 generations

A Japanese team conducted a serial cloning study starting from one female mouse, re-cloning for 57 generations and producing over 1,200 offspring. By generation 58, accumulated genetic mutations and loss of the X chromosome caused the re-cloned mice to die shortly after birth, effectively ending the line. Crossbreeding later-generation clones with normal mice showed initially normal litter sizes but reduced fertility in later-generation lines, with partial recovery in descendants. The results support Muller's ratchet and reinforce the idea that sexual reproduction is essential for long-term mammalian survival, limiting the practical viability of endless cloning.

Gene conversion sustains selection in a clonal Amazon molly genome
science1 month ago

Gene conversion sustains selection in a clonal Amazon molly genome

Researchers show that the clonal Amazon molly uses gene conversion to sustain natural selection: it creates new clonal lineages by reverting or fixing mutations and resolves incompatibilities between parental haplotypes, slowing degenerative mutation accumulation (Muller’s ratchet) while preserving parental divergence and altering chromatin organization in the transition to clonality.