Summary Genes & Genomes

A snapshot of the summary - Genes & Genomes

• 1 Week 1

• 1.1 Lecture

• Name some important reasons why genetic diagnoses are important

  Have an explanation, limiting diagnostic circuit, providing treatment, prognosis, information about the disease etc.
• What is a pedigree?

  A family tree showing symbols to visualise generations, sexes and whether or not being affected by a familiar disease
• In what order are family members drawn in a pedigree?

  First the patient, partner, children, parents, siblings, nieces/nephews, grandparents/grandchildren, aunts/uncles, cousins etc. Later the partners family may also be included
• How does one recognise dominant inheritance?

  Many family members having similar symptoms on one side of the family
• What is genotype-phenotype correlation?

  The correlation between specific mutations and their phenotype. For example knowing that mutations in bp 0-150 have effect X and mutations in bp 150-300 have effect Y etc.
• What are mosaic mutations?

  Dominant mutations that are not somatic in parents, but do occur in newborns. These have occured in oocytes or sperm cells, meaning they have effect after fertilisation.
• What level of dominance do most mosaic mutations have?

  These are usually dominant mutations
• How does one recognise recessive inheritance?

  Affected children are usually born to unaffected parents. Both parents are carriers, 2 carrier parents have a 25% chance to have an affected child
• What is a specific feature of X-linked recessive inherited diseases?

  Mostly boys are affected, females can be carriers
• Why is it possible for women to have some symptoms of X-linked recessive diseases?

  Due to the Lyon hypothesis, which states that each cell inactivates one of the X-chromosomes randomly. So roughly 50% of their tissue has an effective mutation