Testcross and gene linkage
2,457 views · Published 10 July 2014 · 10:09 · Indexed 25 October 2026
Channel: Nikolay's Genetics Lessons · 2014 · Education
In genetics, a test cross, first introduced by Gregor Mendel, involves the breeding of a dominant trait individual with a recessive individual, in order to determine the zygosity of the former by analysing proportions of offspring with the recessive phenotype. The genotype that an offspring has for each of its genes is determined by the allele inherited from its parents. The combination of alleles is a result of the maternal and paternal chromosomes contributed from each gamete at fertilization of that offspring. During meiosis in gametes, homologous chromosomes experience genetic recombination and segregate randomly into haploid daughter cells, each with a unique combination of maternally and paternally coded genes.[1] Test crosses involve breeding the individual in question with another individual that expresses a recessive version of the same trait. If all offspring display the dominant phenotype, the individual in question is homozygous dominant; if the offspring display both dominant and recessive phenotypes, then the individual is heterozygous.
More from this channel
-
5:53
Gene expression
-
9:07
What are the Light and Heavy strands of DNA?
-
17:08
Mitosis and meiosis
-
14:48
Haplodyploidy in honeybees
-
7:12
Single stranded DNA
-
4:51
How message RNA is read: duplets, triplets or tetraplets?
-
4:11
Gregor Mendel, questions and facts
-
8:21
Сongenital baldness inheritance in birds ZZ/ZW