Qbank-Mendelian Genetics

Mendelian Genetics
Pdf Summary
The document is a collection of questions and explanations related to various aspects of Mendelian genetics. Here are summaries of the key questions and concepts addressed:<br /><br />1. **Autosomal Recessive Disorder Frequency**: Based on Hardy-Weinberg equilibrium, the calculation methods are used to determine the frequency of normal alleles in a population. For a disorder with a frequency of 1 in 2500, the population with two copies of the normal allele is approximately 96%.<br /><br />2. **Carrier Probability and Genetic Counseling**: It examines the likelihood of a child inheriting an autosomal recessive disorder, with specific probabilities involved in carriers passing mutations to offspring.<br /><br />3. **X-linked Dominance and Sex Ratio**: Discussed is an X-linked dominant trait, specifically hypophosphatemic rickets, and the expected male-to-female ratio of affected individuals.<br /><br />4. **Germline Mosaicism**: The case of osteogenesis imperfecta type 1 in a family without prior history, highlighting germline mosaicism as a possible explanation.<br /><br />5. **Three-Allele Locus on X Chromosome**: Inquiries into inheritance patterns when the locus affects color vision, illustrating how transmission results in all sons affected with green blindness from a specific parental genotype combination.<br /><br />6. **Pedigree Analysis**: Several questions relate to interpreting pedigrees, identifying inheritance patterns such as autosomal dominant, X-linked recessive, or mitochondrial, and explaining them with genetic concepts like genomic imprinting or digenic inheritance.<br /><br />7. **Syndrome Identification**: Specific genetic syndromes like Prader-Willi or Alagille syndrome are identified based on characteristic symptoms, linking them to genetic causes.<br /><br />8. **Triplet Repeat Disorders**: Genetic anticipation is presented as a hallmark of disorders caused by triplet repeat expansions.<br /><br />9. **Inheritance Risk Estimations**: The document provides explanations for calculating the risk of passing on genetic disorders, like cystic fibrosis and type 1 albinism.<br /><br />10. **Hardy-Weinberg and Assortative Mating**: Assortative mating, which can affect genetic equilibrium, is illustrated through examples such as couples with similar genetic conditions choosing to mate.<br /><br />This covers various genetic disorders, inheritance patterns, and diagnostic/genetic counseling considerations pertinent to Mendelian genetics.
Keywords
Mendelian genetics
autosomal recessive
Hardy-Weinberg equilibrium
X-linked dominance
germline mosaicism
pedigree analysis
genetic syndromes
triplet repeat disorders
inheritance risk
assortative mating