Molecular Genetics (Lec. 20 - 21)

Lectures 20-21

Eukaryotic Gene Generalized Structure

DNA (makes code to build proteins) → mRNA → Protein (goes into ribosomes & collects amino acids to build polypeptide chain)

Chromosomes

Composed of DNA & proteins, contained in the cell nucleus (Makes up genetic info).

Gene

Functional segment of all genetic material in 1 complete set of chromosomes (ability for animals to exist, all information)

Genome

Sum of all genetic material in 1 complet4e set of chromosomes (ability for animals to exist, all information).

Autosomes

Any chromosomes that aren’t sec chromosomes, occurs in pairs in diploid organisms.

Sex Chromosomes

Determine the sex of an organism, different between the sexes.

mRNA process

Goes into cell, makes codes, & communicates to ribosomes to create chains & proteins for protein synthesis.

Mitosis

Duplicates info so each new cell gets the information. Genetic info is split into daughter cells/gametes & crosses over to have a mix of parent information.

Meiosis

A 2-step call division that creates genetically unique haploid gametes from a diploid cell (production of gametes)

Meiosis 1

Cells separate homologous chromosomes pair, cutting chromosomes numbers in half & creating 2 different cells.

Meiosis 2

Those 2 cells then separate sister chromatids, producing 4 unique haploid gametes

Locus

Site/location on a chromosome were a certain gene produces a certain trait

Alleles

different versions of a gene

Number of allele in a locus

Only 2 alleles at a locus in an inividual

Genotype

Genetic constitution/makeup of an individual

Homozygous

Both alleles are identical (AA, aa)

Heterozygous

Alleles are different (Aa)

Phenotype

Combination/sum of genotype + environment. Results from action of genetic (G) makeup of an organism, its environment (E), and the interaction between the genes & environment. P = G + E + (G x E)

Drives which alleles are present

Phenotype

Determines which alleles are present

Meiosis

Principle of Segregation

Each gamete will have 1 allele at any given locus

Principle of Independent Assortment

Different allele pairs segregate independently

Dominant: AA = Aa

Heterozygous, same phenotype

Co-dominance: AA cant equal Aa

Effect of both alleles observed

Epistasis

When phenotype of 1 gene depends on or is modified by other genes