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  2. Hybrid zone - Wikipedia

    en.wikipedia.org/wiki/Hybrid_zone

    Hybrid zones can form from secondary contact. A hybrid zone exists where the ranges of two interbreeding species or diverged intraspecific lineages meet and cross-fertilize. . Hybrid zones can form in situ due to the evolution of a new lineage [1] [page needed] but generally they result from secondary contact of the parental forms after a period of geographic isolation, which allowed their ...

  3. List of unsolved problems in chemistry - Wikipedia

    en.wikipedia.org/wiki/List_of_unsolved_problems...

    RNA folding problem: Is it possible to accurately predict the secondary, tertiary and quaternary structure of a polyribonucleic acid sequence based on its sequence and environment? Protein design : Is it possible to design highly active enzymes de novo for any desired reaction?

  4. Eukaryote hybrid genome - Wikipedia

    en.wikipedia.org/wiki/Eukaryote_hybrid_genome

    An example of a homoploid hybrid genome is a schematic of the mosaic genome of the Italian sparrow which is a hybrid resulting from the house sparrow P. domesticus which spread across the Mediterranean with agriculture and encountered and hybridized with local populations of Spanish sparrow P. hispaniolensis [48,49,85].

  5. Bent's rule - Wikipedia

    en.wikipedia.org/wiki/Bent's_rule

    The hybrid can certainly be normalized, as it is the sum of two normalized wavefunctions. Orthogonality must be established so that the two hybrid orbitals can be involved in separate covalent bonds. The inner product of orthogonal orbitals must be zero and computing the inner product of the constructed hybrids gives the following calculation.

  6. Introgression - Wikipedia

    en.wikipedia.org/wiki/Introgression

    Introgression is an important source of genetic variation in natural populations and may contribute to adaptation and even adaptive radiation. [7] It can occur across hybrid zones due to chance, selection or hybrid zone movement. [8]

  7. Secondary contact - Wikipedia

    en.wikipedia.org/wiki/Secondary_contact

    A hybrid zone may appear during secondary contact, meaning there would be an area where the two populations cohabitate and produce hybrids, often arranged in a cline. The width of the zone may vary from tens of meters to several hundred kilometers. A hybrid zone may be stable, or it may not.

  8. Orbital hybridisation - Wikipedia

    en.wikipedia.org/wiki/Orbital_hybridisation

    Chemist Linus Pauling first developed the hybridisation theory in 1931 to explain the structure of simple molecules such as methane (CH 4) using atomic orbitals. [2] Pauling pointed out that a carbon atom forms four bonds by using one s and three p orbitals, so that "it might be inferred" that a carbon atom would form three bonds at right angles (using p orbitals) and a fourth weaker bond ...

  9. Isovalent hybridization - Wikipedia

    en.wikipedia.org/wiki/Isovalent_hybridization

    In chemistry, isovalent or second order hybridization is an extension of orbital hybridization, the mixing of atomic orbitals into hybrid orbitals which can form chemical bonds, to include fractional numbers of atomic orbitals of each type (s, p, d). It allows for a quantitative depiction of bond formation when the molecular geometry deviates ...