Answer:
stretching them back and forth
Explanation:
Explanation:
The problem says that the hairless phenotype never breeds true. That means that it's not the result of a homozygous genotype (H₁H₁ or H₂H₂), so it is caused by the heterozygous genotype (H₁H₂).
The <u>expected </u>offspring from the cross between two Mexican hairless would be:
<h3>P
H₁H₂ x
H₁H₂</h3><h3>F1 1/4
H₁H₁, 2/4
H₁H₂ and 1/4
H₂H₂.</h3>
And the <u>expected</u> phenotypic ratio 3:1. However, the observed offspring shows a 2:1 ratio. What's happening?
If the observed phenotypic ratio in the offspring of a monohybrid cross (a single gene with two alleles) is 2:1, we can suspect that one of the genotypes is lethal in homozygosis and therefore does not appear in the progeny (the puppies are born dead).
If we proposed that the H₂ allele is lethal in homozygosis, then:
- The H₁H₁ genotype would cause normal puppies --> 1
- The H₁H₂ genotype would cause hairless puppies --> 2
- The H₂H₂ is lethal and causes the death of puppies --> 0
The phenotypic ratios change to 2:1, as observed in the experiment.
Mutations and natural selection cause adaptations. Mutations can cause instant adaptations, while natural selection is the process by which adaptations occurs over a series of generations.
Adaptations are changes or processes of changes by which an organism or species becomes better suited for its environment.
A mutation is an alteration of the DNA sequence. Sometimes such alterations code for the same amino acid sequence as the unaltered DNA strand during protein synthesis. In such a circumstance, the mutation is not detectable. However, other mutations alter the genetic code in such a way that a noticeable change in the trait that is associated with that gene is visible. Sometimes such mutations are advantageous and improve the organism's ability to survive in its environment.
Natural selection is the process by which organisms with more advantageous traits (being camouflaged, being covered with the correct outer covering for the temperatures of that environment, stronger/ larger/ or faster to fight off or run from predators, etc.) are more likely to survive in a particular environment. Likewise, organisms less advantageous traits are more likely to die due to the pressures exerted by the environment (such as temperature, predators, illness, etc.). Therefore, the organisms with the advantageous traits that survive are more likely to survive to find a mate and reproduce. Thus, the advantageous traits are passed down to future generations.
<u><em>Hope this helps because I was learning about this today! </em></u>
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<u><em>Soruces that might help: </em></u>
brainly.com/question/6836560
