Dihybrid test cross or back cross
This presentation is the property of its rightful owner.
Sponsored Links
1 / 17

Dihybrid test cross or back cross PowerPoint PPT Presentation


  • 593 Views
  • Uploaded on
  • Presentation posted in: General

Dihybrid test cross or back cross. Dihybrid test cross/back cross. As in monohybrid crosses, you can’t tell by looking at the dominant trait whether it is homozygous or heterozygous. Dihybrid test cross/back cross.

Download Presentation

Dihybrid test cross or back cross

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Dihybrid test cross or back cross

Dihybrid test cross or back cross


Dihybrid test cross back cross

Dihybrid test cross/back cross

  • As in monohybrid crosses, you can’t tell by looking at the dominant trait whether it is homozygous or heterozygous.


Dihybrid test cross back cross1

Dihybrid test cross/back cross

  • As in monohybrid crosses, you can’t tell by looking at the dominant trait whether it is homozygous or heterozygous.

  • So in order to find out what the genotype is – do a test cross with an organism that has both recessive characteristics.


Dihybrid test cross back cross2

Dihybrid test cross/back cross

  • As in monohybrid crosses, you can’t tell by looking at the dominant trait whether it is homozygous or heterozygous.

  • So in order to find out what the genotype is – do a test cross with an organism that has both recessive characteristics.

  • If the parent is heterozygous you get a ratio of 1:1:1:1


Dihybrid test cross back cross3

Dihybrid test cross/back cross

  • As in monohybrid crosses, you can’t tell by looking at the dominant trait whether it is homozygous or heterozygous.

  • So in order to find out what the genotype is – do a test cross with an organism that has both recessive characteristics.

  • If the parent is heterozygous you get a ratio of 1:1:1:1

  • If it is homozygous, all the offspring will show the dominant phenotype for both characteristics.


Example

Example

Genotype:AaBbxaabb

Gametes:


Example1

Example

Genotype:AaBbxaabb

Gametes: AB AbaBabab


Example2

Example

Genotype:AaBbxaabb

Gametes: AB AbaBabab

Punnett Square:


Example3

Example

Genotype:AaBbxaabb

Gametes: AB AbaBabab

Punnett Square:


Example4

Example

  • Now, you have an organism that is homozygous dominant for one trait, but heterozygous for the other – the test cross/back cross still works.


Example5

Example

  • Now, you have an organism that is homozygous dominant for one trait, but heterozygous for the other – the test cross/back cross still works.

  • In the cross:

  • For the homozygous dominant characteristic, no recessive trait will show up in the offspring


Example6

Example

  • Now, you have an organism that is homozygous dominant for one trait, but heterozygous for the other – the test cross/back cross still works.

  • In the cross:

  • For the homozygous dominant characteristic, no recessive trait will show up in the offspring

  • For the heterozygous characteristic the recessive trait will show up


Example7

Example

Genotype:AABbxaabb

Gametes:


Example8

Example

Genotype:AABbxaabb

Gametes: AB ABAbAbabababab


Example9

Example

Genotype:AABbxaabb

Gametes: AB ABAbAbabababab

PunnettSq:


Example10

Example

Genotype:AABbxaabb

Gametes: AB ABAbAbabababab

PunnettSq:


Example11

Example

Genotype:AABbxaabb

Gametes: AB ABAbAbabababab

PunnettSq:

  • ALL show the dominant trait for A and HALF show the recessive trait for B. From this, you can deduce the genotype as AA for trait A and Bb for trait B


  • Login