Flashcards in Backcross Method Deck (6)
What is the main objective of the Backcross Method?
Qualitative improvement, by focusing on ONE trait.
What is the fundamental process of the Backcross Method?
Repetitve crosses of outlying progeny with specific parent... 2nd donor parent only used once in initial cross.
What is the general formula for recovery of recurrent parental of selected genotype?
1 - (1/2)^(N + 1)
where N = # of backcrosses
Why do procedures differ in Backcross Methods?
Exact procedures depend on:
- Inheritance of trait of interest
- How trait is evaluated.
Discuss steps of Backcrossing a dominant gene.
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 ...
4. BC6F1 Aa, selfed. -> BC6F2 = 1/4 AA : 1/2 Aa : 1/4 aa ... evaluate / elimate aa!
5. Self AA's and Aa's -> BC6F2:3 rows = 1/3 AA : 2/3 segregate.
6. Bulk AA's and release!