Basics and Essentials of Human Genetics

Explore the structure of nucleic acids, including DNA and RNA, their nucleotides, sugars, bases, and the phosphodiester backbone, plus base pairing and double-stranded antiparallel DNA.

Explore why thymine, created from uracil by DNA methyltransferase, protects DNA from nucleases, stabilizes base pairing with adenine, and reduces mutations, while uracil in RNA remains less stable.

Differentiate nucleosides from deoxynucleosides by the attached sugar: ribose versus deoxyribose. When sugar bonds, bases form adenosine, guanosine, cytidine, uridine, and thymidine.

Explore Huntington's disease as an autosomal dominant, chromosome 4 disorder caused by CAG expansion in the huntingtin gene, and analyze inheritance patterns with Punnett square scenarios.

Explore Huntington's disease as an autosomal dominant disorder caused by CAG repeats in huntingtin gene, diagnosed via genetic testing, with chorea, cognitive and behavioral changes, and prospects for gene therapy.

Learn the key symptoms of sickle cell anemia, including anemia, pain crises, swelling, infections, and growth delays. Explore treatments from hydration and transfusions to vaccines and emerging gene therapy.

Explore cystic fibrosis as an autosomal recessive disorder caused by CFTR mutations on chromosome 7 that disrupt chloride transport, thickening mucus in the lungs, pancreas, and other organs.

Explain diagnosis of cystic fibrosis through sweat electrolyte testing with pilocarpine and chloride and sodium thresholds, and outline CFTR genetic testing via the acmg/acog 23‑mutation panel, pcr, and sequencing.

Explore how cftr mutations disrupt chloride transport, causing thick mucus in cystic fibrosis. Review respiratory and digestive symptoms, plus infertility in men and bone health impacts.

Explore alkaptonuria, an autosomal recessive inherited metabolic disorder caused by homogentisate dioxygenase deficiency, leading to homogentisic acid buildup that turns urine black and causes ochronosis and kidney stones.

Explore alkaptonuria as an autosomal recessive disorder caused by hgd gene mutations that reduce homogentisate dioxygenase activity, leading to homogentisic acid buildup and missense, nonsense, and frameshift mutations.

Explore frame-shifting indel mutations in the hgd gene of alkaptonuria, altering the reading frame to produce a nonfunctional protein with a premature stop codon and homogeneous acid buildup.

Explore the xx xo system of chromosomal sex determination, where females have two X chromosomes and males have one X (no second X), with corresponding gamete types.

Explores androgen insensitivity syndrome, an X-linked recessive condition where defective androgen receptors in an XY individual prevent androgen signaling, leading to cryptorchid testes, breast development, and female-appearing phenotype.

Explore how X-linked color blindness arises from genes on the X chromosome affecting red and green cone detection, while blue detection lies on chromosome 7.

explains how x-linked red-green color blindness is inherited, detailing the x chromosome alleles x^c and x^+, carrier and hemizygous states, and parental cross scenarios that yield gender-based probabilities.

Initiate primary hemostasis by platelets adhering to exposed subendothelial collagen via integrin α2β1 and GPVI and binding von Willebrand factor through GPIb-IX-V, following vessel injury.

Explore the intrinsic pathway of secondary hemostasis, detailing activation of factors 12, 11, 9, 8, and 10, thrombin generation from prothrombin, and fibrinogen to fibrin with factor 13 cross linking.

Explain autosomal dominant inheritance and pedigree patterns, including autosomal versus dominant, heterozygous and homozygous genotypes, and Punnett square scenarios with 50/50 and 25% outcomes.

Explore autosomal dominant inheritance, homozygous and heterozygous genotypes, and Punnett square analysis, with recurrence and occurrence risk guiding genetic counseling.

Explore X-linked dominant inheritance through pedigree analysis, showing how the X chromosome drives disease expression in males and females, and how homozygous and heterozygous states shape offspring risk across generations.

Explore X-linked recessive inheritance and pedigree patterns, showing how affected males inherit from mothers and how carrier females transmit to offspring, illustrated with Punnett squares.