Examples of surface tension:
-
Walking on water: Small insects such as the water strider can walk on water because their weight is not enough to penetrate the surface.
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Floating a needle: A carefully placed small needle can be made to float on the surface of water even though it is several times as dense as water.
Answer:
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 pigment
- M is dominant over m
- If D is present, M/m is expressed
- If dd is present, M/m is not expressed
- DDMM, DdMM, DDMm, DdMm --->Black fur
- DDmm, Ddmm ---> Brown fur
- ddMM, 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)
