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Mimicry in Papilio is controlled by more than one genetic locus:

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    In this topic, we will discuss the special character Mimicry in Papilio. The swallowtails have a global distribution and Papilio is the largest genus of them; their most striking characteristic is a “tail” on the hindwing. Swallowtail butterflies come in many colors gorgeous greens, subtle shades of reds and orange, and marbled patterns in white and gray a but the commonest type has stripes of black and yellow called tiger swallowtail or Papilio glaucus it’s female called Papilio nigra has black, with red spots on its hindwings. This species is not poisonous but it mimics pipevine swallowtail Battus philenor, which is poisonous. and birds don’t prey upon them.

    tiger swallowtail
    1. P.memnon is another case in which the male is deep blue in color and have black stripes
    2. P. memnon females come in an almost numberless variety. Their forewings show different geometric patterns of black and white
    3. Their hindwings, as well as varying in shape, can be colored in yellow, orange, or blood red,
    4. They may or may not have a bright white spot
    5. Some have tails, others do not
    6. The abdomen varies in color and a spot at the butterfly’s “shoulder” (i.e., at the base of the forewing near the head) called the epaulette, may be present in various shades of reds.

    Clarke and sheppard work

    They suggested that each female mimics a different model.

    Clarke and Sheppard were interested in the genetic control of this complex mimetic polymorphism. Crosses between the various morphs initially suggested that a single genetic locus, with many alleles, is at work. Because offsprings usually contain one of the parent’s character after the cross. This suggested the same phenomena is occurring like one dominant and other recessive. but later on, this concept got complicated.

    When they studied Anura specie they interpreted that

    Anura’s morphology mixes patterns from two of
    the common morphs: it has the wing color pattern of the morph Achates but it lacks Achates’ tail.
    Clarke and Sheppard’s interpretation is that Anura is not an allelic variant, but a recombinant, and that the mimetic patterns of P. memnon are not controlled by one locus but by a whole set of loci. If Anura is recombinant, then there must be at least one locus say T controlling the presence allele T+ or absence T– of a tail and at least one other locus C controlling the color patterns C1 for Achates, and C2, C3, etc., alleles for other color morphs.

    Achates would have a genotype made up of one or two
    sets of the two-locus genotype T+C1 and Anura would have T–C1, after recombination between a tailless morph and Achates.

    More than five loci are involved in mimicry model

    From anura alone, at least two loci could be inferred to control the mimetic polymorphism of P. memnon; but other rare morphs have also been found. Some rare morphs, for example, combine the forewing color of one morph and the hindwing pattern of another, suggesting that separate loci control the color of the fore- and hindwings. When all the inferred recombinants are considered together, at least five loci seem to be at work: T, W, F, E, and B. They control, respectively, the presence or absence of tail, hindwing pattern, forewing pattern, epaulette color, and body color.

    The anura morph is a recombinant between the T locus and the other four. The common morphs, which mimic natural models, should each consist of a particular set of alleles at the five loci. The morph mimicking model species no. 1, for example, might have genotype T+W1F1E1B1/T+W1F1E1B1, and another morph (mimicking a second model) might have T–W2F2E2B2/T–W2F2E2B2 or T–W2F2E2B2/T+W1F1E1B1.

    conclusion

    The polymorphism in swallowtail butterflies is controlled by multilocus genotype.

    Reference: Evolution by Mark Ridley

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