Abacus College, Oxford

Many factors can affect gene expression. Some cause the expression of traits to deviate from the patterns predicted by Mendelian inheritance.

Genetic diagnostic technology is rapidly improving. A small amount of DNA can be amplified using the polymerase chain reaction (PCR) process, which can produce millions of copies of a gene or gene segments.

Genetic testing is used to diagnose many disorders (eg, Turner syndrome, Klinefelter syndrome, hemochromatosis). Diagnosis of a genetic disorder often indicates that relatives of the affected person should be screened for the genetic defect or for carrier status.

Mitochondrial disorders can be due to mitochondrial or nuclear DNA abnormalities (eg, deletions, duplications, mutations). High-energy tissues (eg, muscle, heart, brain) are particularly at risk of malfunction due to mitochondrial abnormalities.

For many traits, expression involves multiple genes. Many such traits (eg, height) distribute as a bellshaped curve (normal distribution). Normally, each gene adds to or subtracts from the trait independently of other genes.

A gene, the basic unit of heredity, is a segment of DNA containing all the information necessary to synthesize a polypeptide (protein). Protein synthesis, folding, and tertiary and quaternary structure ultimately determine much of the body’s structure and function.

Genetic disorders determined by a single gene (Mendelian disorders) are easiest to analyze and the most well understood. If expression of a trait requires only one copy of a gene (one allele), that trait is considered dominant. If expression of a trait requires 2 copies of a gene (2 alleles), that trait is considered recessive. One exception is X-linked disorders. Because males usually have no paired allele to offset the effects of most alleles on the X chromosome, the X chromosome allele is...

Certain situations represent aberrant inheritance, often because genes or chromosomes are altered. However, some of these alterations, such as mosaicism, are very common; others, such as polymorphisms, are so common that they may be considered normal variants

HESI EXIT RN 2022 V2 160 QUESTIONS WITH ANSWERS NEW2022/2023:LATEST ,A+ GRADED DOCUMENT[100% GUARANTEED.

The notes for the IB course of Math Analysis and Approaches - by an IB student of M22 achieving 45 points (7 for Math predicted and achieved). Notes are handwritten and organized by subchapter in mind-map concise and thorough format. All you need to achieve a 7 in IB Math is contained within the note-set for this subject. Contains only relevant information that gets asked in exams and topic tests - summarized from the Companion Course-books (Pearson and Oxford). Perfect for revision purposes and...