Thekey differencebetween test cross and backcross is that the测试十字是在主要之间发生的十字架phenotype而后串是固定表型,而后交叉是在generation F1hybrid and one of the two parents.
Understanding the difference between test cross and backcross is important in genetics as they are two different types of crosses that are extremely helpful to identify the genotype of an animal or a plant. The major objective of performing the test cross and backcross is to discover theheterozygosity or homozygosity of individuals通过识别类型gametesthat produce the dominant genotypes.
Consider the following example to understand both crosses and the difference between test cross and backcross. Here, ‘T’ denotes the dominant trait of the tall pea plant, and ‘t’ denotes the recessive trait of the same phenotype. A tall pea plant hybrid can either exist as homozygous (TT) or heterozygous (Tt) and the dwarf plant hybrid is always homozygous recessive (tt).
内容
1.Overview and Key Difference
2.What is Test Cross
3.什么是反向交叉
4.测试交叉和反向交叉之间的相似之处
5.并排比较 - 表格形式的测试交叉与反向交叉
6。概括
What is Test Cross?
在测试交叉中,F1混合动力车与隐性父母交叉。换句话说,测试交叉是主要表型(TT或TT)和纯合隐性(TT)之间的交叉。门德尔(Mendel)是第一个执行测试杂交的人,以确定个人是杂合的还是纯合特征。除了发现杂合性外,测试十字架还可用于检查父母产生的配子的纯度。
If a homozygous dominant F1 hybrid (TT) crosses with the recessive parent, it will always result in 100% heterozygous tall hybrids. The below figure explains this.
If a heterozygous dominant F1 hybrid (Tt) crosses with the recessive parent, only 50% will be tall, and the rest 50% will be dwarf. The below image explains this.
什么是反向交叉?
In backcross, the F1 hybrid is crossed back with any of the parent, either dominant or recessive. Backcrosses increase the useful traits in a population. For example, certain crop plant hybrids are backcrossed with wild species to recover their useful traits such as disease resistance, high yield, etc.
However, this process may dilute the other useful traits of hybrid. In order to overcome this disadvantage, hybrids are backcrossed repeatedly with its parent plants over a few generations to receive their good traits back into the new hybrids.
What are the Similarities Between Test Cross and Backcross?
- Test cross and backcross are useful in plant and animal breeding.
- 他们解释了生物体的表型和基因型以及它们如何传递给下一代。
- All test crosses are backcrosses.
- They determine the genotype of an individual as well as help to recover important characteristics.
- In both, the crossing is between unknown genotypes.
What is the Difference Between Test Cross and Backcross?
Test cross and backcross are two types of popular crosses in plant breeding. Test cross happens between a dominant phenotype with the recessive phenotype to determine the genotype of the dominant phenotype. Backcross helps to recover important characters of the parent population within hybrid populations.
概括– Test Cross vs Backcross
All test crosses are a type of backcross, but all back crosses are not test cross. During the backcross, the crossing back of the F1 hybrid is with any of the parents, either homozygous or heterozygous. However, during the test cross, the crossing back of the F1 hybrid is always with the recessive parent. A test cross is important to determine the genotype (TT or Tt) of the dominant phenotype while backcross is useful in recovering important characteristics of the parent. This is the difference between a test cross and backcross.
Reference:
1.“Backcrossing.” Egyptian Journal of Medical Human Genetics, Elsevier.Available here
2. Nature News,Nature Publishing Group。Available here
Image Courtesy:
1.”Inbreeding- Backcross”By Donach – Own work,(CC BY-SA 4.0)viaCommons Wikimedia
Varahamihir Gupta说
所以可以测交F2和recessiv之间e parent Or is it restricted to F1 only?
Hasa说
Test cross is always done for the determination of zygosity (homozygous or heterozygous) of a dominant phenotype. Hence, a particular dominant phenotype is crossed with its recessive phenotype. The dominant phenotype can be obtained either from F1 or F2. However, the phenotype subjected to a test cross should be dominant.