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Two genes are located on the same chromosome and are known to be
A. If the testcross produces 1000 offspring, what are the predicted numbers of offspring with each of these four genotypes:
B. What would be the predicted numbers of offspring with the four genotypes if the parental generation had been
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Genetics: Analysis and Principles
- If two gene pairs A and a and B and b are assorting independently with A dominant to a and B dominant to b, what is the probability of obtaining: a. an AB gamete from an AaBb individual? b. an AABB zygote from an AaBb x AaBb cross? c. an aaBb offspring from an AaBB x aabb cross? d. a phenotype aB from an Aabb x aaBb cross? e. an ab gamete from an aaBB individual?arrow_forwardTwo genes, A and B, are 10 map units apart along the same chromosome. A cross was made between AAbb and aaBB individuals to produce AaBb F1 offspring. The F1 offspring were then crossed to aabb individuals to yield an F2 generation. What would be the genotype(s) of F2 offspring that carry recombinant chromosomes? (Note: recombinant chromosomes are the product of crossing over). What percentage of F2 offspring would be Aabb?arrow_forwardThe A locus and the D locus are so tightly linked that norecombination is ever observed between them. If Ad/Ad is crossed with aD/aD and the F1 is intercrossed,what phenotypes will be seen in the F2 and in whatproportions?arrow_forward
- Individuals of genotype AaBb were mated to individuals of genotype aabb. One thousand offspring were counted, with the following results: 474 Aabb, 480 aaBb, 20 AaBb, and 26 aabb. What type of cross is it? Are these locilinked? What are the two parental classes and the two recombinant classes of offspring? What is the percentage of recombination between these two loci? How many map units apart are they?arrow_forwardTo determine the recombination frequency between body color and wing genes in flies, you perform several crosses where you cross an F1 having red body and smooth wings with a yellow-bodied, crinkle-winged fly. You get the following results. What is the distance between the genes for body color and wing surface in map units?arrow_forwardConsider the genetic map below. (a) In a total of 1000 observed progeny, how many would be expected to be parental, non-recombinant? (b) If the total number of observed double-crossover recombinant progeny is 0, what is the interference? A-------20 cm-----B—5cm----Carrow_forward
- Two pure-breeding parents produced a heterozygous female offspring (AaBb) that was then testcrossed with an aabb male. The offspring produced from the testcross included 50 AaBb, 450 Aabb, 450 aaBb, 50 aabb individuals. Describe how you can tell if these two genes are linked or unlinked (What ratio would you expect to see from the testcross if they were not linked?). What were the genotypes of the original parents that produced the heterozygous female? What is the genetic map distance between the two genes?arrow_forwardConsider the genetic map below. (a) In a total of 1000 observed progeny, how many would be expected to be parental, non-recombinant? (b) If the total number of observed double-crossover recombinant progeny is 0, what is the interference? Show step by step A-------10cm-----B—2.5cm----Carrow_forwardWhen a white guinea pig is crossed to a yellow guinea pig, all the progeny are cream-colored. From a cross of two such F1’s, the F2 showed 32 white, 66 cream, and 30 yellow guinea pigs. How is this trait inherited? _______________ Identify the genotype of the white guinea pig. ________ Identify the genotype of the yellow guinea pig. ________ Identify the genotype of the cream-colored guinea pig. ________ Identify the genotypes and the corresponding phenotypes of the F2 progeny. Give the genotypic ratio. __________________ Give the phenotypic ratio. ___________________arrow_forward
- What is the difference between a monohybrid cross and a dihybrid cross? A. A monohybrid cross involves a single parent, whereas a dihybrid cross involves two parents. B. A monohybrid cross produces a single progeny, whereas a dihybrid cross produces two progeny. C. A monohybrid cross involves organisms that are heterozygous for a single trait, whereas a dihybrid cross involves organisms that are heterozygous for two traits. D. A monohybrid cross is performed only once, whereas a dihybrid cross is performed twice.arrow_forwardIf genes A and B are linked, how would you figure out what would be the expected percentages of nonrecombinant and recombinant progeny in a test cross of AaBb heterozygotes?arrow_forwardIn an autotetraploid Chinese primrose (Primula sinensis), the gene controlling stigma color is very near the centromere of the chromosome carrying it. The allele G for green stigma is dominant to g for red stigmas. A homozygous green autotetraploid strain is crossed with a homozygous red autotetraploid strain. a. What phenotypic ratio of green to red is expected if: The F1’s are intercrossed? The F1’s are crossed with red plantsarrow_forward
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