Molecular Markers in Molecular Breeding Quiz

Di-Nucleotide Repeat Motif in Plants

• The most abundant di-nucleotide repeat motif in plants is (AT) n, indicating a high frequency of adenine and thymine pairs.

AT-Enrichment and SSR Markers

• Lack of AT-enrichment methods for SSR markers primarily stems from the difficulty in isolating sequences with high adenine-thymine content effectively due to their repetitive nature.

Suitability of SSR Markers in Map-Based Cloning

• SSR markers are ideal for map-based cloning due to their high polymorphism levels, co-dominant inheritance, and ability to amplify products of variable lengths for precise mapping.

Polymorphisms in SSRs

• SSR polymorphisms can be distinguished based on the length of PCR products; variations in length correspond to differences in the number of repeat units in the DNA sequence.

DNA Polymorphisms from Tandem Repeats

• DNA polymorphisms arise from differences in the number of tandem repeated DNA sequences at a specific locus on a chromosome, leading to variability in genomic structure.

AFLP Molecular Marker Technique

• AFLP employs PCR amplification of genomic restriction fragments created by specified restriction enzymes, combined with selected oligonucleotide adapters.

Ligating DNA Fragments in AFLP

• Specific adaptors are used to ligate to the ends of the DNA fragments in AFLP, allowing for subsequent amplification and analysis.

Purpose of AFLP in Molecular Breeding

• AFLP is utilized in molecular breeding for genetic diversity assessment, marker-assisted selection, and creation of genetic maps.

Restriction Enzymes Used in AFLP

• Typically, restriction enzymes used in AFLP for digesting genomic DNA include EcoRI and MseI, chosen for their ability to cut at specific sequences.

DNA Fingerprinting with AFLP

• AFLP acts as a DNA fingerprinting technique due to its capacity to produce a unique pattern of bands based on the fragment sizes of amplified products, reflecting genetic variation.