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Principles of Inheritance and Variation

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Biology

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Biology

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CBSE Gujarat Board Haryana Board

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Class 10 Class 12

Which one of the following is an example of polygenic inheritance?

  • Flower colour in Mirabilis jalapa

  • Production of male honey bee

  • Pod shape in garden pea

  • Skin colour in humans


D.

Skin colour in humans

Polygenic inheritance involves the determination of a particular phenotypic characterisitc by many genes, called polygenes (i.e., the group of genes influencing a quantitative characteristic), each having a small effect individually.
The characteristics controlled in this way show continuous variation and are called polygenic characters e.g., height and skin colour in humans.
The polygenic inheritance is called multifactorial inheritance or quantitative inheritance.
The pink flower colour in Mirabilis jalapa is an example of incomplete dominance while production of male honey bee is an example of parthenogenesis.

Polygenic inheritance involves the determination of a particular phenotypic characterisitc by many genes, called polygenes (i.e., the group of genes influencing a quantitative characteristic), each having a small effect individually.
The characteristics controlled in this way show continuous variation and are called polygenic characters e.g., height and skin colour in humans.
The polygenic inheritance is called multifactorial inheritance or quantitative inheritance.
The pink flower colour in Mirabilis jalapa is an example of incomplete dominance while production of male honey bee is an example of parthenogenesis.


What for symbols AA and Aa stand ?

AA : Homozygous dominant, Aa : Heterozygous dominant.

Mention the phenomenon of pleiotropy by giving an example.

Pleiotropy. When one gene controls more than one phenotypic character it is termed as pleiotropy.

Example : Sickle cell anaemia.


Name the plant that shows incomplete dominance in respect of the colour of its flower.

The plany which shoes incomplete dominace in respect of the colour of its flower is -

Snapdragron ( Antirrhinum majus)

Or 

Mirabilis jalapa (Four-O- Clock plant ).

Give one example of genetic trait for each of the following in humans : (i) Lethality (ii) Multiple allelism.

(i) Lethality : Sickle cell anaemia.

(ii) Multiple allelism : ABO blood groups.


Name one trait that does not blend.

Sex trait .