Centro Metric Combination - Assignment Example

Genetics Question a The general formula for the number of different male or female Centro metric combinations possible is given by 2n; where n is the number of different chromosome pairs. Since this is a diploid cell, we need to find the total number of different pairs of chromosomes which is n. We have 2n=8Which means that, n=8/2 Therefore n= 4This will give us the total number of ways, which is: 24= 16 ways.b.) Since the flies are unrelated, it implies that both flies have genes on separate chromosomes in each fly.

Thus, they are homozygous across their genome. When they are crossed, we find that they are identical to each other with heterozygous genomes. Since 2 chromosome pairs are equal to 22 combinations of gametes, the chromosomal combination for two unrelated flies is given by the formula:2n*2 for a diploid cell, where n =4, Thus we have 24*2= 256 combinations.c.) A gamete is a cell that contains only one set of dissimilar chromosomes or half the genetic material that is necessary to form a complete organism.

A genotype is the specific set of alleles inherited at a locus. The alleles are found on these chromosomes which make up the genotype. Therefore, from the total number of gametes produced, we can tell the number of genotypes produced is n from the diploid cell. The total chromosome combinations are 256 as seen in (b) above. Thus, if we compare genotypes with the total gametes, we have 4:256. Simplifying the ratio we get 1:64. This means that for every 1 genotype, there are 64 possible chromosome combinations.

Question 2 An organism is considered a pure breed if it is homozygous; it has a pair of identical alleles. To get the potential parental gametes we foil the genotypes by separating the alleles; just like in meiosis. We, therefore, write down the cross in terms of the parental genotypes and phenotype: Parental phenotypes white eyes with curly wings * red eyes with normal wings Parental genotypes wwCy Cy * W+ W+ cy + cy+Crossing these two pure breeds, we get a dihybrid with W+w Cy cy+ genotypes as the F1 generation.

The dihybrid cross gives us W+ Cy, W+ cy+, w Cy, and w cy+ as the gametes. All the four gametes produced are different but they have equal proportions. Moreover, the gametes randomly come together to produce a zygote with each trait having a 25% chance of being inherited. This is well illustrated by the Punnet square below: KEY: GenotypePhenotypeRed eyes, curly wingsWhite eyes, curly wingsWhite eyes, normal winged eyes, normal wingsThe phenotypic ratio is 9(red with curly wings): 3(white eyes with curly wings):3(white eyes with normal wings):1(red eyes with normal wings).