Incomplete dominance:
Correct answer: C. The phenotype of the heterozygote is intermediate between phenotypes of the two homozygotes.
- A. Different alleles of a gene are both expressed in heterozygous condition
- B. One allele is completely dominant over the other and the presence of the recessive allele is functionally hidden so the heterozygote has the same round phenotype as homozygote.
- C. The phenotype of the heterozygote is intermediate between phenotypes of the two homozygotes.
- D. Gene mutations may produce many different alleles of a gene.
Explanation
Option C is correct. Incomplete dominance is a type of genetic inheritance in which the phenotype of the heterozygous offspring is intermediate between the phenotypes of the two homozygous parents. For example, in peas, the allele for purple flowers (P) is dominant over the allele for white flowers (p). However, when a heterozygous plant (Pp) is crossed with another heterozygous plant (Pp), the offspring will not be all purple or all white. Instead, they will be a mix of both colors, with some plants having more purple flowers and others having more white flowers. This is because the dominant allele for purple flowers only partially masks the expression of the recessive allele for white flowers. In other words, both alleles are expressed to some extent, resulting in an intermediate phenotype.
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About Inheritance
Mendel's laws explain segregation, independent assortment and the prediction of genetic ratios using alleles, genotypes and phenotypes. The chapter also covers linked genes, recombination and crossing over during meiosis, then applies pedigree reasoning to X-linked recessive traits, which show different inheritance patterns in males and females.
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