Which one of the following options best represents the sequence of events leading to the phenomenon of introgression?
hybridization, back crossing and stabilization
Introgression is a genetic process where genes are transferred from one species into the gene pool of another species through repeated backcrossing of an interspecific hybrid with one of its parents.
Introgression Process Steps
The phenomenon of introgression typically involves a sequence of events that allows genetic material from one population or species to become incorporated into another. The key steps are:
- Hybridization: This is the initial step where two different species or populations interbreed to produce a hybrid offspring. This hybrid carries a mix of genetic material from both parent populations. However, hybrids are often less fertile or viable than the parent species, which can limit further gene flow.
- Back crossing: Following hybridization, the hybrid offspring must successfully reproduce with one of the parental species (often referred to as the "recurrent parent"). This backcrossing needs to happen repeatedly over several generations. Each backcross generation results in offspring that are progressively more similar genetically to the recurrent parent, but they still retain some genes from the other parent species (the "donor parent"). This repeated mating with the recurrent parent is crucial for diluting the genetic contribution of the donor parent while potentially retaining some specific beneficial genes.
- Stabilization: In this final phase, the introgressed genes (those from the donor species) that have been transferred through backcrossing become established and stable within the gene pool of the recurrent parent population. This means these genes are successfully passed down through generations and contribute to the genetic variation of the recipient species. This stabilization can occur if the introgressed genes provide some adaptive advantage or are linked to genes that do, or simply by chance (genetic drift) if the population is small.
This sequence ensures that while a hybrid is initially formed, the repeated backcrossing allows for the selective transfer and integration of specific genetic segments from the donor species into the recipient species, leading to introgression.
Important Questions from Breeding
Which of the following is an indigenous dairy breed of cattle?
Given below are a few statements on use of plant breeding to develop improved varieties of a crop plant:
A: Genotypic/phenotypic variation in the desired trait should be available in the germplasm resources of the crop plant.
B: Availability of molecular markers linked to the trait of interest would decelerate the process of trait introgression into desired varieties.
C: Breeding procedures to improve plant varieties are generally more successful among sexually compatible species as compared to sexually incompatible species.
D: Co-dominant molecular markers cannot be used for selection of plants with the desired trait.
Which of the above statement(s) is/are INCORRECT?
Given below are some terms in column A and their corresponding properties/related terms in column B
Which one of the following options represents the most appropriate match between all terms of column A and B?Column X Column X A Bulk segregant
analysis(i) QTL analysis of wider genetic diversity using fewer individuals B NILS (ii) Mapping monogenic qualitative trails C Association mapping (iii) Co-dominant markers D SNPs (iv) Repeated backcrossing of F1 to recurrent parent Which one of the following approaches/markers would be typically used for discovering polymorphism between two closely related accessions of a crop plant?
A group of researchers are testing two new agents, M1 and M2 for their efficacy in selecting transgenic plants. When they performed tissue culture experiments using three explants, A, B, and C without Agrobacterium transformation, and selected the regenerated plants on M1 and M2, the following regeneration frequencies were obtained.
Regeneration frequencies (%) in presence of different concentration of agents Explant type M1 conc. (mg/L) M2 conc. (mg/L) 20 60 100 10 15 20 A 44% 21% Nil 8% Nil Nil B 53% 30% 10% Nil Nil Nil C 71% 42% 18% 15% 9% 4% Based on the above data, which one of the following conclusions is INCORRECT?
