Syntenic genes are located on the same chromosome.
Independent assortment results in recombinant chromosomes.
You can reliably predict the relative genetic distance fromgenesâ physical distance on a chromosome.
Linked genes are always syntenic.
What is the relative genetic distance between two linked genesif the recombination frequency is 0.49?
What statement best explains the distortion in Mendelian ratiosobserved by Bateson & Punnett in 1905? (Reminder: they found anoverrepresentation of F2 offspring showing both dominant orrecessive phenotypes, and an underrepresentation of offspringdisplaying one dominant and one recessive phenotype)
Human error: they should have been more careful about theirexperimental setup.
Gene linkage: Genes for flower color and pollen shape arephysically close on the same chromosome, leading to a breakdown inthe independent assortment of the alleles for these traits.
Chromosome crossover: Homologous recombination of twochromatids during meiosis caused the alleles to shuffle, resultingin a breakdown of the independent assortment of the alleles forthose genes.
Random variation: No two situations are alike. In finitepopulations, you are going to get some variation across a mean.
When determining the relative genetic distance between twogenes, why is dihybrid back-cross preferable over traditionaldihybrid cross?
9:3:3:1 phenotypic ratio is easier to work with than 1:1:1:1ratio.
Genotypes of the offspring can be determined based on theirphenotype.
If the genes are independently assorted, the dihybrid back-crosswould result in only 2 genotypes in the F1 generation.
What is your best guess for which marker is more closely linked to a gene that influences height?
A) Marker 1
B) Marker 2
22. Two pure breeding parents produce red and white flowers. They are crossed and the F1 produces pink flowers. When the F1 are selfed to produce the F2, nine distinct classes of pigmentation are present among F2 individuals. What is your best guess of the minimum number of genes that underlie flower pigmentation in this species?
23. In a quantitative genetic experiment you identify two genes that confer bands of color on the back of a fly. At each gene, a dominant allele causes one band of color. If flies that are heterozygous at both loci are crossed, what ratio of offspring do you expect in each phenotype (i.e., number of color bands) class? (answer options are given from lowest to highest band number)