Genetic Linkage

4. Clear wing, Black eye, and Hairless (c, b, and h) are linked, recessive traits carried on

Suppose the feather color of a bird is controlled by two alleles, D and d. The D allele results in dark feathers, while the d allele results in lighter feathers.

This Punnet Square represents the F1 offspring breeding with each other to create more offspring. This second set of offspring is the F2 generation. If both parents are heterozygous dominant, then the offspring expected would be: 50% heterozygous dominant, 25% homozygous dominant and 25% homozygous recessive.

2. How will the alleles for these traits assort into the gametes that each parent might produce? (Hint: For a reminder on how alleles sort independently into gametes, refer to the illustration in Part 2, Question 2, in the Student Guide.)

Part C: Assume that the genes from the previous example are located along the chromosome

Introduction: The intention of this lab was to gain a better understanding of Mendelian genetics and inheritance patterns of the drosophila fruit fly. This was tasked through inspecting phenotypes present in the dihybrid crosses performed on the flies. An experimental virtual fly lab assignment was also used to analyze the inheritance patterns. Specifically, the purpose of our drosophila crosses is to establish which phenotypes are dominant/recessive, if the traits are inherited through autosome or sex chromosomes and whether independent assortment or linkage is responsible for the expressed traits.

Now you have determined some facts about the grounded allele and the trait that it causes. Given what you know, do you expect the mutant F1 flies to be homozygous or heterozygous for the allele that causes the grounded trait? According to your reasoning, if you mated two mutant F1 flies, what percentage of flies would you expect to be wild type versus mutant in the F2 progeny? Draw a Punnett square of this cross to justify your answer.

The Chi squared analysis supported that ratio matched our expected ratio (X²=3.0, p>0.05). This ratio suggests that the vestigial trait is autosomal recessive. It is thought to be autosomal because there is not a noticeable pattern between the traits that are expressed amongst males and females. The progeny of the cross between the sepia females and the wild type males also displayed a 3:1 ratio. This ratio lined up with our expected ratio (X²=0.09, p>0.05).

The Unknown Drosophila Cross Abstract: Genetics is the study of genes, heredity, and variation in living organisms.. Heredity is the passing of traits to offspring from its parents (Bechtel). This is the process by which an offspring cell or organism acquires or becomes predisposed to the characteristics of its parent cell or organism. These characteristics are in a physical sense are known as phenotypes and genotypes in the genetic sense. In the lab, we studied Mendelian Genetics through a common insect of a fruit fly, formally known as Drosophila Melangaster.

Abstract The objective of this lab to, develop an understanding of the inheritance patterns observed in a fruit fly. For this experiment we used Drosophila melanogaster as a model organism due to its short life cycle, small size, and its virtual inexpensiveness. Drosophila melanogaster commonly known as the fruit fly used in this experiment provided experimental data that was in agreement with the laws of segregation and independent assortment proposed by Gregor Mendel.

Based on your results for the female offspring, predict whether color blindness is a dominant or recessive trait. Explain your reasoning.

For our first generation (F1) of flies we chose to cross apterous (+) females and white-eye (w) males. We predicted that the mutation would be sex linked recessive. So if the female was the sex with the mutation then all females would be wild type heterozygous. Heterozygous is a term used when the two genes for a trait are opposite. The males would all be white eye since they only have one X chromosome. If the males were the sex that had the mutation then all the flies would be wild type but the females would be heterozygous.

This experiment looks at the relationship between genes, generations of a population and if genes are carried from one generation to another. By studying Drosophila melanogaster, starting with a parent group we crossed a variety of flies and observe the characteristics of the F1 generation. We then concluded that sex-linked genes and autosomal genes could indeed be traced through from the parent generation to the F1 generation.

This table helps show all the possible genotypes from one set of parents. The table shows that the genotypes purple and starchy are dominant, and the genotypes yellow and sweet are recessive.(stallsmith)

The pairs of alternative traits examined segregated among the progeny of a particular cross, some individuals exhibiting one traits, some the other