Genetics: Multifactorial Disorders and Gene Regulation

• A multifactorial genetic disorder is caused by a combination of multiple genes and environmental factors
• Heart disease is an example of a multifactorial genetic disorder
• Mitochondrial diseases are inherited through the mother via the egg cell
• The mother's mitochondrial DNA is inherited by all of her children, regardless of their sex
• Alzheimer's disease can be an example of a polygenic (multifactorial) disorder
• A nucleosome is the basic unit of chromatin structure
• Nucleosomes help package and organize DNA within the nucleus, making it more compact and accessible for processes like replication and transcription
• In human males, meiosis is initiated and continues at puberty
• Promoters and enhancers are located in the 5' region of human genes; they are regulatory sequences that control gene expression
• Promoters are regions where RNA polymerase binds to start transcription
• Enhancers are sequences that boost gene transcription by interacting with transcription factors
• Ribonucleic acid (RNA) has mRNA, rRNA, and tRNA
• Gene families arise primarily through gene duplication, where a gene is copied within the genome
• DNA sequences that resemble known genes but are nonfunctional are called pseudogenes
• Capping, polyadenylation, and splicing are steps a primary RNA transcript undergoes before it becomes a fully processed, mature mRNA
• Methylation of cytosine phosphate guanine (CpG) islands is associated with transcriptional repression
• RNA splicing allows a single gene to produce multiple gene products
• Copy Number Variations (CNVs) can cause duplication or deletion of large DNA segments
• Microsatellite is not a structural variant
• Single Nucleotide Polymorphisms (SNPs) can influence an individual's response to medications and disease risk
• Cells are arrested in metaphase for routine karyotyping because the chromosomes are most condensed and visible then
• Acrocentric chromosomes have satellites attached to their short arms by stalks
• Chromosomal nondisjunction is the most common cause of chromosomal aneuploidy, the failure of chromosomes to separate properly during cell division
• Whether the abnormal gamete contributed two copies of the same chromosome or one of each homolog is needed in determining a nondisjunction event
• The techniques in order from largest to smallest genetic abnormality that can be detected are G-banding -> Fluorescent in situ hybridization (FISH) -> Comparative genome hybridization -> Allele specific oligonucleotide hybridization
• The term for a chromosome in which one arm is deleted and the other arm is duplicated in a mirror image fashion is mirrored chromosome

Explanation of multifactorial genetic disorders caused by multiple genes and environmental factors. Covers mitochondrial inheritance, nucleosomes, gene regulation via promoters and enhancers, and the timing of meiosis in human males.