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NEW THINKING. "This hypothesis, known as the duplication-degeneration-complementation (DDC) process, posits that degenerative mutations may knock out independent subfunctions encoded by discrete regulatory elements in duplicate genes, thus requiring preservation of both copies in order to maintain the full complement of ancestral gene functions." https://lnkd.in/eHCDVhZ View in LinkedIn

NEW TWIST. "Duplicate genes show evidence of purifying selection more consistent with buffering of the ancestral gene function than neofunctionalization reconciled Ohno's original theory with more recent observations by proposing subfunctionalization as a means of preserving duplicate genes in the presence of degenerative mutations targeting both members of a duplicate pair." https://lnkd.in/eHCDVhZ View in LinkedIn

POOR THEORETICAL FIT. "The preservation of large numbers of duplicate genes derived from ancient polyploidy events is difficult to reconcile with a model in which null alleles at duplicate loci are easily fixed by genetic drift." https://lnkd.in/eHCDVhZ View in LinkedIn

FATE OF GENES. "Seminal theory concerning the fates of duplicate genes predicted that the duplicate copy would be shielded from purifying selection by the ancestral copy, thus promoting pseudogenization in the absence of positive selection for a rare acquired function." https://lnkd.in/eHCDVhZ View in LinkedIn

EXAPTATION. "Notably, the processes of subfunctionalization and neofunctionalization may not be mutually exclusive. Indeed, the degenerative processes leading to subfunctionalization may act upon silencer elements and thereby promote neofunctionalization." https://lnkd.in/eHCDVhZ View in LinkedIn

GENE FATES AFTER DUPLICATION. "Following duplication, each gene within a paralogous pair may evolve in several ways. For example, it may retain the same set of functions as the ancestral copy, retain only a subset of the original set of functions (subfunctionalization), obtain a new function (neofunctionalization), or degrade into a nonfunctional gene (nonfunctionalization)." https://lnkd.in/eHCDVhZ View in LinkedIn

ENLARGED GENE FAMILIES. "Clusters of duplicated genes have also formed through tandem duplication (TD) processes, which have greatly expanded some gene families, such as the Nucleotide Binding Site-Leucine Rich Repeat (NBS-LRR) subset of plant resistance genes. Unequal recombination is thought to be the primary mechanism driving the expansion of these gene clusters." https://lnkd.in/eHCDVhZ View in LinkedIn

SO ENDS this first weekend on butterfly metamorphosis. What a complicated adaptation to put yourself through, where you basically liquefy your first body and completely reform it into a new one, all the while staying alive and not turning into a pot of cooling stew. Still to this day, despite all the scanning technology, the process is largely inscrutable. View in LinkedIn

MONARCH BUTTERFLY scanned during metamorphosis (page 30-39). https://lnkd.in/ev8dK-4 View in LinkedIn

"TIME-LAPSE three-dimensional imaging inside a living chrysalis." Stunning study of metamorphosis of the Painted Lady butterfly. Overcoming prior technical challenges. https://lnkd.in/eTSQd9X View in LinkedIn