Answer:
e. is under purifying selection
Explanation:
Purifying selection removes deleterious alleles that can arise through
random mutations
.
Mutations may or may not have consequences at the level of genetic expression depending on whether those mutations are synonymous or nonsynonymous. Synonymous mutations do not generate changes in the protein to be encoded while non-synonymous ones do.
Important genes for the development of the organism - such as those involved in the neural development- are very likely to be under purifying selection, eliminating individuals with deleterious alleles since those alleles (product of non-synonymous substitutions) do not allow the individuals to survive.
Answer:
Explanation:
My best bet is DNA methylation at the site of Tweedledum's leptin gene or Histone Acetylation at the site of Tweedledee's gene.
B/c DNA methylation is a process by which methyl groups are added to the DNA molecule. Methylation can change the activity of a DNA segment without changing the sequence. When located in a gene promoter, DNA methylation typically acts to repress gene transcription. So this is probably repressing Tweedledum's leptin gene trancription which is not happening in Tweedledee.
Additionally, Histone Acetylation at site of Tweedledee's gene increases her trancription b/c Histone acetylation causes DNA to be more accessible and leads to more transcription factors being able to reach the DNA. Thus, acetylation of histones is known to increase the expression of genes through transcription activation.
In order for offspring to have a dominant mutation, they need at least one copy of the allele from either or both parents. So yes, at least one of the parents must have the mutated gene in order for the offspring to have the mutation.
For your second question, I'm not quite sure what you mean so I will restate two possibilities for what I think you mean:
1. The offspring does not have the mutation if none of the parents have the mutated gene: this is correct.
2. If the mutation is recessive and the child has only one copy of the mutated allele, then the child will not show the mutation. If none of the parents had the mutated gene, then it would not be possible for the child to have the mutated gene or show it.
B. You can survive and get materials then find a way back
