In cats, the Dense pigment gene, D/d, codes for melanophilin, a protein involved in the transportation and deposition of pigment into a growing hair. A separate gene, M/m, is responsible for the production of the pigment, with M_ producing black pigment and mm producing brown. When a cat has two recessive d alleles, its fur is a light gray color regardless of which alleles of M/m are present. Required:
State the phenotype and frequency for each of the following outcomes of a dihybrid cross:

a. M_D_
b. M__dd
c. mmD
d. mmdd

a. M_D_ : 9/16 Black furred individuals

b. M__dd : 3/16 gray furred individuals (1/16 MMdd + 2/16 Mmdd)

c. mmD_ : 3/16 Brow-furred individuals (1/16 mmDD + 2/16 mmDd)

d. mmdd: 1/16 gray furred individuals.

Explanation:

Available data:

Dense pigment gene, D, codes for melanophilin.D allele dominant over d. Gene M/m is responsible for the production of the pigmentM is dominant over mIf D is present, M/m is expressedIf dd is present, M/m is not expressed  DDMM, DdMM, DDMm, DdMm --->Black furDDmm, Ddmm ---> Brown furddMM, ddMm > Light gray fur

Cross: between two dihybrids

Parental)         DdMm     x     DdMm

Phenotype) Black-furred      Black-furred

Gametes) DM, Dm, dM, dm   DM, Dm, dM, dm

Punnet Square)    DM        Dm         dM          dm

             DM       DDMM    DDMm   DdMM   DdMm

             Dm       DDMm    DDmm   DdMm   Ddmm

             dM        DdMM    DdMm    ddMM   ddMm

             dm        DdMm    Ddmm    ddMm   ddmm

F1) 9/16 Black-furred individuals, D-M- (1/16 DDMM + 2/16 DDMm + 2/16    

                                                                 DdMM + 4/16 DdMm)

    3/16 Brown-furred individuals, D-mm ( 1/16 DDmm + 2/16 Ddmm)

    4/16 Gray-furred individuals, dd-- ( 1/16ddMM + 1/16 ddmm + 2/16 ddMm)

   

   

Mantle convection  is the slow  creepingmotion of earth's solid silicate  mantle  caused by  convection  currents carrying  heat from the interior  to the planet's surface.[1][2]  the earth's surface  lithosphere, which rides atop the  asthenosphere  (the two components of the  upper mantle), is divided into a number of  plates  that are continuously being created and consumed at their opposite  plate boundaries. accretion occurs as mantle is added to the growing edges of a plate, associated with  seafloor spreading. this hot added material cools down by  conduction  and  convection  of heat. at the consumption edges of the plate, the material has thermally contracted to become dense, and it sinks under its own weight in the process of  subduction  usually at an  ocean trench.[3]this subducted material sinks through the earth's interior. some subducted material appears to reach the lower mantle,[4]  while in other regions, this material is impeded from sinking further, possibly due to a phase transition from  spinel  to  silicate perovskiteand  magnesiowustite, an  endothermic reaction.[5]the subducted oceanic crust triggers  volcanism, although the basic mechanisms are varied. volcanism may occur due to processes that add buoyancy to partially melted mantle causing an upward flow due to a decrease in density of the partial melt.secondary forms of convection that may result in surface volcanism are postulated to occur as a consequence of intraplate extension[6]  and  mantle plumes.[7]it is because the mantle can convect that the  tectonic plates  are able to move around the earth's surface.[8]mantle convection seems to have been much more active during the  hadean  period, resulting in gravitational sorting of heavier molten  iron, and  nickel  elements and  sulphides  in the core, and lighter  silicate minerals  in the  mantle.

Probably a behavioral adaptation