DNA Sequencing in Genome Projects — NEET Biology
📚 Practice ConceptAre extensively used as a starting point in the sequencing of whole genomes as was done in the case of the Human Genome Sequencing Project, described later.
Match the following genetic patterns with their underlying mechanisms and associated conditions: Column I (Genetic Pattern) A. Pleiotropy B. Polygenic Inheritance C. Codominance D. Point Mutation E. Aneuploidy Column II (Underlying Mechanism/Description) I. A single gene affects multiple, seemingly unrelated phenotypic traits. II. Multiple genes contribute additively to a single phenotypic trait. III. Both alleles of a gene are fully expressed in the heterozygote. IV. Alteration of a single base pair in the DNA sequence. V. Gain or loss of one or more chromosomes. Column III (Associated Condition/Phenotype) P. Mental retardation, reduced hair/skin pigmentation Q. Human skin colour, showing a continuous gradient R. ABO blood grouping, where IA and IB are both expressed S. Sickle-cell anaemia, specifically the GAG to GUG substitution T. Down's syndrome, due to trisomy of chromosome 21
View solution & NCERT explanation
Correct answer: A — A-I-P; B-II-Q; C-III-R; D-IV-S; E-V-T
This question requires matching genetic patterns with their mechanisms and classic examples/conditions as described in NCERT. A. Pleiotropy: A single gene affects multiple phenotypic traits (Column II-I). Phenylketonuria is a classic example mentioned in NCERT, characterized by mental retardation and reduced hair/skin pigmentation (Column III-P). So, A-I-P is correct. B. Polygenic Inheritance: Multiple genes contribute additively to a single phenotypic trait (Column II-II). Human skin colour is explicitly given as a classic example in NCERT, showing a continuous gradient (Column III-Q). So, B-II-Q is correct. C. Codominance: Both alleles of a gene are fully expressed in the heterozygote (Column II-III). ABO blood grouping, where both IA and IB alleles are expressed when present together, is a perfect example (Column III-R). So, C-III-R is correct. D. Point Mutation: This refers to a change in a single base pair of DNA (Column II-IV). Sickle-cell anaemia is the classical example of a point mutation, specifically the GAG to GUG substitution in the beta-globin gene (Column III-S). So, D-IV-S is correct. E. Aneuploidy: This is the gain or loss of a chromosome(s) due to failure of segregation of chromatids during cell division (Column II-V). Down's syndrome, caused by trisomy of chromosome 21 (an extra copy of chromosome 21), is a common example of aneuploidy (Column III-T). So, E-V-T is correct. All the matches in option A are consistent with the NCERT text. This comprehensive matching question integrates multiple genetic concepts and disorders discussed in the chapter.
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Through deep analysis of NEET and NTA, 176 of the 180 ReNEET 2026 (June 21) questions were already in the MedicNEET question bank before the exam.
176/180MedicNEET's Biology question bank is built from the same NCERT lines NTA picks repeatedly. Not random MCQs — questions crafted exactly like NTA crafts them.