5 public questions tagged with this topic.
Down’s syndrome is caused by trisomy of chromosome 21, leading to developmental and cognitive impairments.
Ref: NCERT Class 12 Biology Chapter 4: Principles of Inheritance and Variation Chromosomal Theory Linkage Recombination Gene Mapping
Down’s syndrome is caused by trisomy of chromosome 21, leading to developmental and cognitive impairments.
Ref: NCERT Class 12 Biology Chapter 4: Principles of Inheritance and Variation Polygenic Inheritance Pleiotropy and Quantitative Inheritance
Down’s syndrome is caused by trisomy of chromosome 21, leading to developmental and cognitive impairments.
Ref: NCERT Class 12 Biology Chapter 4: Principles of Inheritance and Variation Monohybrid Dihybrid and Test Cross
Down syndrome most common viable autosomal aneuploidy, frequency about 1 in 700 births rising sharply with maternal age after 35 years due prolonged oocyte arrest. Cytogenetically majority cases free trisomy 21 with 47,XX+21 or 47,XY+21 karyotype showing extra small acrocentric chromosome in metaphase. Phenotype includes characteristic facial appearance upslanting palpebral fissures, single palmar crease, hypotonia, intellectual disability variable, increased risk congenital heart defects, duodenal atresia, early Alzheimer-like pathology by fourth decade. Chromosome 21 smallest autosome contai
Ref: Lewis, Human Genetics, 12th ed., Chapter 9: Down Syndrome Trisomy 21 Phenotype and Karyotype
M-FISH uses combinatorial fluorescence strategy where each chromosome is painted with a unique combination of fluorochromes, creating a distinct spectral signature decoded by software. Down syndrome results from trisomy 21. In M-FISH, chromosome 21 probes labeled with a specific fluorochrome combination appear thrice per metaphase spread instead of twice, readily identified by extra same-colored chromosome and automated image analysis. Color-coded fluorophores thus enable rapid whole-karyotype screening without chromosome-specific conventional G-banding expertise. Probe size, RNA tagging, and
Ref: NCERT Biology Class XII Principles on Klenow fill-in labeling, Lehninger Chapter 9 DNA cloning techniques, and Molecular Cloning by Sambrook Chapter 10 documenting end-labeling of cohesive termini.
