In the fly lab you will be recombining chromosomes from two strains of flies. Th

Question

In the fly lab you will be recombining chromosomes from two strains of flies. The first strain is a multiply marked mutant strain that is homozygous for mutant alleles at four X-linked loci: yellow body color, crossveinless wings, vermillion eye color, and forked bristles. The second strain is a wildtype strain called Oregon-R (named for where it was collected) that carries wildtype alleles at all four loci. When you have females that are heterozygous for these two chromosomes, recombination will occur, producing progeny that inherit X chromosomes from their mother that contain mixtures of these markers. Keeping in mind that all four of these loci are on the X chromosome, answer the following questions. If you crossed Oregon-R females to y cv v f males, what are all of the genotypes and phenotypes that you expect to find in the F1 generation? If you do the cross in the other direction (using y cv v f females and Oregon-R males), what are all of the genotypes and phenotypes that you expect to find in the F1 generation? Suppose you were to sib-mate F1 males and females within the two cases above. Would you be able to see recombination in all or some of the F2 in each case? Why or why not? Why can recombination only occur in females for X-linked traits? In lab, you will be given some F1 progeny (males and females). These F1 flies are from a cross between one sex from the multiply marked stock and the other sex from Oregon-R, but you do not know which sex came from which stock. Your task in lab will be to figure out the genotypes of the parents think about what you would see in each case!

Explanation / Answer

1) The 2 genes back jointly anew in the children. All the next generation will be heterozygous. placing them back jointly get phenotype all black and genotype BbRr (100%), rough coat.

Classic dihybrid traverse (copulation two F1 dihybrids jointly) so the next generation phenotype will by in the anticipate 9:3:3:1 ratios - 9 commanding in both trait (rough, black, ), 3 commanding in 1 research and recessive in the additional (black, smooth), 3 commanding in the other research and recessive in the other research (albino, rough) and 1 recessive in couples of traits (smooth, albino).

4. 1. More familiar in males
2. Simulated males proceed research to girls (carriers)
3. Female transporter proceed research to throughout 50% of offspring
4. Can skip production.

Sex Linked - -Color Blindness-

-Color blindess is an imperfect term to report a lack of perceptual susceptibility to determined colors, a more accurate phrase is - (CVD) Color Vision Deficiency

Males: (CVD) Color Vision Deficiency 10-20% possess some vision color shortage
-Females: Little fraction of the citizens have any color visual shortage.

-Sex-linked research - X chromosome
-Sex-effect traits - not connection to the X chromosome, but utterance of the trait conflict dependent on the sex of the independent.

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