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In biology, homology is similarity in anatomical structures or genes between organisms of different taxa due to shared ancestry, regardless of current functional differences. Evolutionary biology explains homologous structures as retained heredity from a common ancestor after having been subjected to adaptive modifications for different ...
Sequence homology is the biological homology between DNA, RNA, or protein sequences, defined in terms of shared ancestry in the evolutionary history of life. Two segments of DNA can have shared ancestry because of three phenomena: either a speciation event (orthologs), or a duplication event (paralogs), or else a horizontal (or lateral) gene ...
Whereas ordinary homology is seen in the pattern of structures such as limb bones of mammals that are evidently related, deep homology can apply to groups of animals that have quite dissimilar anatomy: vertebrates (with endoskeletons made of bone and cartilage) and arthropods (with exoskeletons made of chitin) nevertheless have limbs that are constructed using similar recipes or "algorithms".
Comparative anatomy is the study of similarities and differences in the anatomy of different species. It is closely related to evolutionary biology and phylogeny [ 1 ] (the evolution of species). The science began in the classical era , continuing in the early modern period with work by Pierre Belon who noted the similarities of the skeletons ...
When structures in different species are believed to exist and develop as a result of common, inherited genetic pathways, those structures are termed homologous. For example, the leaves of pine, oak, and cabbage all look very different, but share certain basic structures and arrangement of parts. The homology of leaves is an easy conclusion to ...
[2] [9] He forms a structuralist picture of evolutionary developmental biology, using empirical evidence, arguing that homology and biological novelty are key aspects requiring explanation, and that developmental bias (i.e. structural constraints on embryonic development) is a key explanation for these. [10] [11]
This is different from homology, which is the term used to characterize the similarity of features that can be parsimoniously explained by common ancestry. [1] Homoplasy can arise from both similar selection pressures acting on adapting species, and the effects of genetic drift. [2] [3]
In 1977, a revolution in thinking about evolution and developmental biology began, with the arrival of recombinant DNA technology in genetics, the book Ontogeny and Phylogeny by Stephen J. Gould and the paper "Evolution and Tinkering" [28] by François Jacob.