Answer:
e. Red segregated from brown in meiosis I, and straight segregated from curled in meiosis I.
Explanation:
A cross between two flies heterozygous for both genes produced an offspring with the phenotypic ratio of 9:3:3:1. This ratio is expected according to Mendel's law of independent assortment, which states that alleles of the same gene assort independently during gamete formation.
Before meiosis starts in flies, a single diploid cell duplicates its DNA, so each chromosome has 2 sister chromatids that contain the same information.
- During meiosis I, <u>the homologous chromosomes separate</u> into two daughter cells. The chromosome number is reduced by half, but each chromosome has two sister chromatids.
- During meiosis II, <u>the sister chromatids separate</u> and each daughter cell from meiosis I divides into two new daughter cells (to get the total of 4 haploid cells).
In a heterozygous fly, each homologous chromosome contains a different allele, and the sister chromatids are copies that carry the same allele. For that reason, both traits were segregated during meiosis I.
The most likely explanation for the variation is the offspring were produced from different combination of genes. A single pair of gold fish mentioned in the question means a male and a female gold fish. The two of them mated and contributed different genes to the fertilized fish eggs, this results in production of various body shape and colouration which is known as variation.
Answer:
the four types of chemical weathering are:
oxidation
hydrolysis
hydration
carbonation
Answer:
The mentioned case is an illustration of the missense mutation. A missense mutation is a kind of nonsynonymous substitution, that is, it is a mutation in which a variation in a solitary nucleotide leads to the formation of a codon, which encrypts for a distinct kind of amino acid.
When a missense mutation takes place within a DNA, a modification in one of the RNA codon sequences results at the time of transcription. This change in codon will ultimately result in the formation of a different amino acid, which gets presented within a protein at the time of translation. Like in the given case, a change in codon resulted in the substitution of the amino acid tyrosine with an amino acid cysteine.
