Genetics help please Genetics help please Question 18 of 29 Incorrect Mapoft Sap

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Genetics help please Genetics help please Question 18 of 29 Incorrect Mapoft SaplingPlus by Macmllar Learig Genetics Essentials: Co White (w) coat color in guinea pigs is recessive to black (W. In 1909, w. E. Castle and J. C. Phillips transplanted an ovary from a black quinea pi into a white female whose ovaries had been removed. The then mated this white female with a white male. All the offspring from the mating were black in color (W Castle and J. C. Philips, 1909, Science 30:312-313). Which of the following statements explains the results of this cross? O The eggs from the ovary of the black coat guinea pig were likely fertilized by a o The researchers failed to remove the original ovaries of the white female before adding the ovaries from the black guinea pig The white fernale was heter s for the black trait, which explains how the Ooftspring inherited the trait for black coats o The black coats likely arose from mutations that occurred from the transplanting of o The color of the offspring was determined by genes in the transplanted ovary, not the ovaries. the genes of the female who gave birth. Question continues, Scroll down. Give the genotype of the offspring from this cross. O Both WW and ww are likely genotypes. Previous Check Answer NextExit

Explanation / Answer

First Question:

The answer will be the color of the offspring was determined by genes in the transplanted ovary, not the genes of the female who gave birth (Last option).

Explanation: Guinea pig females produced primary oocyte in their early development & in the transplanted ovary already contain primary oocytes which are dominant for black color. As already ovaries of white female guinea pig is removed gametes is produced from the transplanted ovaries only. Thus, here genes responsible for skin color of white female guinea pig don't matter & the genes present in the transplanted ovary only matter.

Second Question:

The answer will be Ww (Third option).

Explanation: The phenotype of white male is ww. White male contributed 'w' in the gametes. White female contribute 'W' from the transplanted ovary in the gametes. So, the genotype of the offspring is Ww.

Third Question:

The answer will be the production of black guinea pig offspring suggests that the allele for black coat color was passed along to the offspring from the transplanted ovary, thus supporting the germplasm theory (Last option).

Explanation: According to pangenesis theory each part of the body contributes heritable information to the gametes. On the other hand according to the germplasm theory, genetic information in the germ-line tissues in the reproductive organs contributes to gamete formation. The black coat color of the offspring suggests that the transplanted ovary contributed genetic information for gamete formation, not alleles of skin coat color of white female. If pangenesis was correct then the skin coat color of the offspring will be white, not black. Thus it supports the germplasm theory.

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