Answer:
75% brown, 25% white
Explanation:
This question involves a single gene coding for color in chickens. The allele for brown color (B) is dominant over the allele for white color (b).
According to this question, a brown rooter with genotype 'BB' was crossed with a white hen (bb). The offsprings in the F1 generation will all possess the 'Bb' genotype and be brown colored. However, if these F1 offsprings are self-mated i.e Bb × Bb, the proportion of F2 offsprings will be 1BB, 2Bb, 1bb.
Since BB, Bb and Bb offsprings are Brown in color and bb is white in color, this means that the expected phenotypic appearance of the F2 offsprings will be:
¾ or 75% brown and ¼ or 25% white
Answer:
4. c. Deletion/ frameshift mutation
5. a. Tyr Tyr Asp Ser Gly
6. A frameshift occurred which altered the identity of the amino acids following the initiator 6. methionine, but not the length of protein Q.
Explanation:
4)
A single base pair at the first position of the Arg codon i.e. CGA has been deleted. Due to the deletion, the reading frame has shifted one nucleotide backwards, altering the amino acid sequence of the protein.
5)
The genomic DNA sequence is 5'-ATG ATA CTA AGG CCC-3'. Therefore, the complementary mRNA will be 5'-UAC UAU GAU UCC GGG-3'. According to the genetic code, this mRNA sequence encodes the following amino acid sequence: Tyr Tyr Asp Ser Gly
6)
The wild type DNA sequence is:
5'-ACUGUAAUGGAGUCAGAUGAUGCAUUAAGGAGAAAUUGAAAUAAA-3'
The mutant i.e. mRNA with the added G will be
5'
ACUGUAAUGGGAGUCAGAUGAUGCAUUAAGGAGAAAUUGAAAUAAA-3'
This is a single base pair insertion and frameshift mutation that shifts the reading frame one base pair forwards. The codon that was originally GAG coding for glutamic acid (Glu) gets converted to GGA that codes for glycine. Therefore, the amino acid sequence has been altered but the polypeptide chain will still have 13 amino acids.
2 amino acids; codon = a triplet & 1 codon codes for 1 amino acid therefore if are 2 mRNA codons then you’ll have 2 amino acids
