Hemophilia, cystic fibrosis, sickle cell anemia

Diabetes, heart disease, cancer

There is mitochondrial genome, Mitochondrial (mtDNA) or nuclear DNA. Ex: Leber hereditary optic neuropathy (LHON), Mitochondrial encephalomyopathy with lactic acidosis and stroke-like episodes (MELAS)

Each nucleotide is composed of a:

Purine bases

Pyrimidine bases

Base pairing occurs between a purine and a pyrimidine

The chain of nucleotides has a ____ orientation

RNA uses _________ → still a pyrimidine base

DNA --> RNA

nucleotides --> DNA

RNA --> Protein

_____________ are the means by which the genes are transmitted from generation to generation

____ contains information coding for proteins

Human genome is organized as __________

The genome of a diploid cell is distributed in ____ chromosomes (____ pairs) → half from mom, half from dad

____ autosomal and ____ sex chromosomes

XX

XY

functional unit in the genome that contains the genetic information for one or more gene products

DNA sequence that encodes the structural compound of a gene product plus regulatory sequences

specific chromosomal location

homologous copy of a gene

normal protein ***

incomplete protein ***

faulty protein ***

Changes the total number of chromosomes

aneuploidy

nondisjunction

Arise from faulty segreation of the chromosome in meiosis or mitosis. Monosomy, trisomy, polysomy

Always clinically evident, and as a rule, they are de novo (i.e., not inherited). Usually do not survive.

involve no loss or gain in chromosomes-not evident clinically

Chromosome abnormalities involve a gain or loss of chromosome segments and are clinically relevant. Can be passed on from generation to generation. Duplications, deletions, inversions, and translocations.

the allele that expresses itself at the expense of an alternate allele; the phenotype that is expressed in the F1 generation from the cross of two pure lines

an allele whose expression is suppressed in the presence of a dominant allele; the phenotype that disappears in the F1 generation from the cross of two pure lines and reappears in the F2 generation

Allele pairs separate or segregate during gamete formation and randomly unite at fertilization

the law of independent assortment; during gamete formation the segregation of the alleles of one allelic pair (shape) is independent of the segregation of the alleles of another allelic pair (color)

genetic makeup

observable results

-Successive generations are affected (vertical transmission).

No “skipped” generations

-One parent should be affected

-Males and females are affected with equal frequency and severity.

-Occurs only in one generation, not in successive generations

-Affects males and females with equal frequency and severity

-Generally rare in population

-Usually result of mating of two carriers (phenotypically healthy)

Result in ¼ normal, ½ carriers like parents and ¼ affected

Higher frequency in the offspring of consanguineous couples (e.g., first-cousin marriage)

Approximately ½ of children will be affected

Daughters inherit

Sons inherit

In X-linked inheritance patterns, there is no male-to-male transmission of the phenotype

In X-linked inheritance patterns, all daughters of an affected male are heterozygous carriers.

All mitochondrial DNA from

No mitochondria in the head of the sperm

If 100% of female children are affected =

Show Gross Chromosomal Changes

can detect genetic disease

Utilizes light microscopy. Cells are grown in a tissue culture, mitosis is chemically inhibited before staining, photographing, sorting, and counting the chromosomes is performed.

Suitable samples include peripheral blood, amniotic fluid, trophoblastic cells from the chorionic villus (umbilical cord), bone marrow and cultured fibroblasts (from a skin biopsy)

Combines cytogenetic and molecular genetic approaches showing chromosome segments in color under the fluorescence microscope

Locus-specific DNA probes allow reliable detection of small microdeletions that are not visible in traditional G-banded chromosome analysis

The DNA from a patient and is combined with the primers in a reaction mixture that replicates and amplifies DNA through a process called polymerase chain reaction (PCR). Following PCR, the amplification products can be further examined with respect to sequence, size, and quantity.

Screening for cystic fibrosis and thalassemias, hemophilia, familial polyposis coli

Separates DNA fragments by size. The molecules to be separated are pushed by an electric field through a gel that contains small pores. Shorter runs faster.

Identifies protein characteristics and effectiveness in vitro

Used to determine the presence or absence of certain proteins (products of genes). Used to look for enzymatic defects.

Best example is Phenylketonuria (PKU) testing → detects deficiency/absence of Phenylalanine Hydroxylase, which is done is all newborn screening.