fly eye color is linked to sex m f 1 males had all red females had either red

Fly eye color is linked to sex m f 1 males had all

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fly eye color is linked to sex (m / f)1.males had all red, females had either red or whitee.Flies, like humans, have X and Y chromosomes.i.fly eye color gene is sex-linkedf.What if the eye color gene is on X chromosome, but not the Y?i.Eye color gene on the x chromosome would determine the dominate characteristic because it is sex linked. g.Only white eyes would require no red eyes alleles which isn’t possible.i.Females have to be homozygous and recessive.19. When are two genes said to be linked?a.Linked genes: genes located on the same chromosome.b.Linked genes can be ‘unlinked’ by crossing over.i.crossing over: genes on the homologous pairsii.Producing offspring with new combinations of alleles and phenotypes!1.recombinants20. For a cross between a parent that is heterozygous for two traits and a parent that is homozygous recessive for the same traits (i.e., a testcross), predict the ratios of phenotypes expected 1) if the genes are not linked (i.e. by independent assortment) and 2) if the genes arelinked, but no crossing over occurs. (For help, refer to Figures 14.8, 15.9, and 15.10.)a.Experiment 2: body color/wing shapei.Body shape1.Gray ( dominant ) b+2.Black bii.Wing shape 1.Normal (dominant) vg+2.Vestigial vgb.b+b+ vg+vg+ ♀ + bb vgvg ♂c.independent assortment
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i.FOIL ii.genes on non homologous chromosomesiii.Independent assortment does NOT apply, because the body color and wing shape genes are LINKED.iv.In the flies it will produce four phenotypesd.If genes aren't linked the phenotype ratios are 1:1:1:1 and if they are linked the ratio is 1:1:0:021. How can parents produce offspring with new combinations of phenotypes 1) with crossing over and 2) without crossing over? a.Crossing over rearranges the DNA sequence by crossing two different chromatids. Without crossing over there is still random fertilization and independetn assortment.22. Review ‘Tips for Genetic Problems’ # 1, 2, 3, 4, and 6. The following genetics problems are suggested for furtherpractice: p. 284-5, #2, 3, 5, 7, 8, 17, and 19 and p. 303-4, #1, 2, 3, 6 a-c.
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