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Flashcards in Backcross Method Deck (6)
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1
Q

What is the main objective of the Backcross Method?

A

Qualitative improvement, by focusing on ONE trait.

2
Q

What is the fundamental process of the Backcross Method?

A

Repetitve crosses of outlying progeny with specific parent… 2nd donor parent only used once in initial cross.

3
Q

What is the general formula for recovery of recurrent parental of selected genotype?

A

1 - (1/2)^(N + 1)

where N = # of backcrosses

4
Q

Why do procedures differ in Backcross Methods?

A

Exact procedures depend on:

  • Inheritance of trait of interest
  • How trait is evaluated.
5
Q

Discuss steps of Backcrossing a dominant gene.

A
  1. Recurrent parent A (aa) x Donor parent B (AA) -> F1 = Aa
  2. aa x F1 Aa -> BC1F1 = 1/2 Aa : 1/2 aa … evaluate / eliminate aa!
  3. aa x BC1F1-> BC2F1 = 1/2 Aa : 1/2 aa … evaluate /eliminate aa!

… repeat …

  1. BC6F1 Aa, selfed. -> BC6F2 = 1/4 AA : 1/2 Aa : 1/4 aa … evaluate / elimate aa!
  2. Self AA’s and Aa’s -> BC6F2:3 rows = 1/3 AA : 2/3 segregate.
  3. Bulk AA’s and release!
6
Q

Discuss steps of Backcrossing a recessive gene.

A
  1. Recurrent parent A (AA) x Donor parent (aa) -> F1 = Aa
  2. AA x F1 Aa -> BC1F1 = 1/2 Aa : 1/2 AA

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