Genetic Terms:

1. Genetics- study of heredity

2. Heredity- passing of traits from parent to offspring

3. Trait- Any characteristic that can be passed from parent to offsprin

4. Allele in Dominant Form- stronger of the 2 genes represented by a capital letter

5. Allele in Recessive Form- gene that shows up less often in a cross; represented by a lowercase letter

6. Genotype- gene combination for a trait

7. Phenotype- the physical feature resulting from a genotype

8. Homozygous Genotype- gene combination involving 2 dominant or 2 recessive genes

9. Heterozygous Genotype- gene combination of one dominant and one recessive allele

10. Monohybrid Cross- cross involving a single trait

 

Mendel's Laws:

Law of Dominance:

• In a cross of parents that are pure for contrasting traits, only one form of the trait will appear in the next generation

• All the offspring will be heterozygous and express only the dominant trait

 

Law of Segregation:

• During the formation of gametes, the two alleles responsible for  trait seperate from each other

• Alleles for a trait are then "recombined" at fertilization, producing the genotype for the traits off the offspring

 

Law of Independent Assortment:

• Alleles for different traits are distributed to sex cells independently of one another

• This law can be illustrated using dihybrid crosses

 

 

Genetic Disorders:

• Most genetic disorders are caused by recessive traits, many of these alleles are rare bt few are common in certain ethnic groups

 

1. Cystic Fibrosis:

   1. Most common genetic disorder by white americans

      1. 1: 20 White Americans carry the recessive trait

      2. 1: 2000 children

2. PKU:

   1. common in people with ancestors in Norway & Sweden

   2. Not detected until infant exhausts all the mothers enzymes and begins to frink milk with the phenyialine the amino acid accumulates and the mental retardation occurs

   3. recessive disorder and preventable by diet

3. Sickle Cell:

   1. condition in which there aren't enough healthy red blood cells to carry adequate oxygen throughout your body. Normally, your red blood cels are flexible and round, moving easily through your blood vessels

 

Simple Dominant Heredity:

• tongue rolling

• earlobe attachment

• hitchhickers thumb

• huntington's disease

• dimples

• widows peak

• pinkles- bent away

• hand clasp

• taste test

 

Dominant Genetic Diseases: 

1. Huntington's Disease:

   1. occurs on chromosome 4

      1. the segment CAG is repeated 10- 35 times

   2. results in the loss of mental 

   3. symptoms begin between 30- 50 years old

   4. no cure

   5. More common

      1. 1: 10,000

 

 

When heredity follows different rules:

1. Incomplete Dominance: 

   1. Incomplete Dominance- the appearance of a third phenotype

   2. homozygous red flower (RR) is crossed with a homozygous (R'R') forms a pink flower

   3. the intermediate pink form of the trait occurs because neither allele of the pair is completely dominant

2. Co- Dominance:

   1. Neither allele is completely dominant over the other. Both alleles are expressed equally. Both phenotypes are shown.

 

Incomplete vs Co- Dominance:

• Incomplete: one allele not completely masking the other

• Co- Dominance: neither allele completely mask one another resukts in expression of both genes

 

Sex Chromosomes:

• Autosome- 22 pairs of matching homologous chromosomes

• Determining the gender of offspring, occurscon the 23rd pair and if female, homologous and same XX

• Male occurs on 23rd pair, but X and Y

 

Sex- Linked Traits:

• Traits controlled by genes located on the sex chromosome

• 2 Recessive Disorders

  • Red/ Green Color Blindness

  • Hemophilia

 

DNA Extraction:

• chemical tratments cause cells and nuclei to burst

• the DNA is inherently sticky, and cqna be pulled out of a mixture

• this is called "spooling" DNA

Cutting DNA:

• restriction enzymes cut DNA   into specific sequences

• useful to divide DNA into manageable fragments

Gel Electrophoresis:

• DNA can be seperated based on size and charge

• DNA is negatively charged

• the phosphate groups are negatively charged

• DNA is placed in a gel and electricity is run through

• negative DNA moves toward the positive end

• Smaller fragments move further and faster

Steps in DNA Sequencing: 

• Many copies of a single strand of DNA are placed in a test tube

• DNA polymerase is added to begin the process

• a mixture of nucleotides is added some of which have dye molecules attached

• each base has different color dye marker

• by chance, some dyed nucleotides and some regular ones are added

• dye moleules are larger and stop the chain from growing

DNA Fingerprint:

• the result is DNA fragments of multiple sizes with color markers that can be identified

DNA Sequencing:

• after the gel seperates the resulting fragments by size, "read" by a DNA sequencing machine from bottom to top

DNA Fingerprinting is Used for.....

• determine paternity/ maternity

• positively ID bodies or stains

• catalog endangered species

Personalized Medicine:

• people with the same genetic similarities

  • greater risk of side effects 

  • severe side effects at relatively low doses

  • no benefit from the treatment

  • the optimal duration of treatment 

• used to improve the selection and dosage of drugs to treat a wide range of conditions

• cardiovascular, lung disease, HIV infection, cancer, arthritis, high cholesterol and depression

 

Copying DNA:

• polymerase chain reaction

• also called PCR Roche in 07- 08

• a method of making many copies of a piece of DNA

PCR:

• large amounts of DNA can be made from a small starting sample

 

Stem Cells:

• Stem Cells ae the basic unit of life

• Stem Cells- is an undifferentiated cell that can divide and give rise to cells that differentiate into specialized cells

• The stem cells in a zygote are undifferentiated. As the cells continue to divide in a zygote embryo, and fetus the cells begin to differentiated, and become specilized, with different structures and different functions.

 

Embryonic Stem Cells:

1. ​Totipotent Stem Cells- egg and sperm unite they create a fertilized egg

2. Piuripotent Stem Cells- when cells differentiate the inner cell mass develops into an embryo

3. Multipotent Stem Cells- cells differentiate a fetus develops can become specialzed cells with specific functions with in an organ systems

 

Adult Stem Cells:

• multipotent cells, undifferentiated cells, present in specific tissue

• chemical signals ,aybe released by one cell to influence the development and activity of another cell