Question

Chapter 9: Patterns of Inheritance
1. Describe the theory of blending hypothesis. Explain why it is rejected.
2. Define and distinguish between true-breeding organisms, hybrids, the P generation, the F 1
generation, and the F 2 generation.
3. Define and distinguish between the following pairs of terms:

• homozygous and heterozygous;
• dominant allele and recessive allele;
• genotype and phenotype.
• Monohybrid cross, dihybrid cross and test cross
4. Understand law of segregation and law of independent assortment
5. Know what autosomal recessive and autosomal dominant disorders mean and how they are inherited
6. Describe the inheritance patterns of incomplete dominance, multiple alleles, codominance,
pleiotropy, and polygenic inheritance.
7. Explain how linked genes are inherited differently from nonlinked genes.
8. Describe patterns of sex-linked inheritance and examples of sex-linked disorders in humans.

Answer 1

Answer=

1. theory of blending hypothesis

The theory of blending hypothesis was a contention given by a biologist Gregor mendel in the 19^thcentury.

It is discredited theory that inheritance of traits from two parents produces offspring with characteristics that are intermediate between those of the parents.

The inheritance pattern of a system involving incomplete dominance ,whereby characters are inherited in heterozygous individuals that show the effect of both alleles.As a result the inherited characters in the offspring are intermediate between those of parents.

Example- Breeding of 2 horses ,one with light color coat,the other dark,would result in offspring that were intermediate between in coat color..If this held true,then eventually all organisms would become more alike in each generation.

It is rejected because: Blending inheritance was the common ideal at that time,but was later discredited by the experiments of Gregor mendel.Mendel proposed the theory of particulate inheritance.

He disproved this theory when he crossed the pollinated tall and short pea plants and the offspring were either tall or short,not medium like the blending of genetics suggests.