If you used a single gene as a probe for FISH on mitotic chromosomes, how many s
ID: 31626 • Letter: I
Question
If you used a single gene as a probe for FISH on mitotic chromosomes, how many spots would light up?
A.One
B. Two
C. Three
D. Four
The answer is D, but why? The teacher said something about diploids and how we have mother and father contributions. I guessed it was 4 because there are 4 chromosomes on it and a single gene probe would light each one up. I guess people thought that meant only 2 would show up because they're sister chromosomes and therefore two duplicates?
Is anyone able to explain? I'm only choosing the best answer for an explanation, not just the answer. I have the answer.
Explanation / Answer
If you used a single gene as a probe for FISH on mitotic chromosomes, how many spots would light up?the unit of heredity most simply defined as a specific segment of DNA, usually in the order of 1000 nucleotides, that specifies a singlepolypeptide. Many phenotypic characteristics are determined by a single gene, while others are multigenic. Genes are specifically located inlinear order along the single DNA molecule that makes up each chromosome. All eukaryotic cells contain a diploid (2n) set of chromosomesso that two copies of each gene, one derived from each parent, are present in each cell; the two copies often specify a different phenotype,i.e. the polypeptide will have a somewhat different amino acid composition. These alternative forms of gene, both within and betweenindividuals, are called alleles. Genes determine the physical (structural genes), the biochemical (enzymes), physiological and behavioralcharacteristics of an animal.
The formation of gametes (sperm, ova) involves a process of meiosis, which allows crossing over between four pairs of chromosomes, twoderived from each parent, which means that new forms of a particular chromosome are created. Gamete formation also results in cells(gametes) with a haploid (n) set of chromosomes that in fertilization creates a new individual, which is a recombinant of 2n chromosomes, halfderived by way of the ovum from the mother and half via the spermatozoa from the father.
Changes in the nucleotide sequence of a gene, either by substitution of a different nucleotide or by deletion or insertion of other nucleotides,constitute mutations which add to the diversity of animal species by creating different alleles and can be used as a basis for genetic selectionof different phenotypes. Some mutations, be they a single base change in a single gene or a major deletion, are lethal.