Unit C: Genetics Flashcards
Gregor Mendel
➼ Mid-19th Century Austrian monk.
➼ Known as the “Father of Genetics.”
➼ Tracked and recorded characteristics in snow peas.
First Filial Generation (F1)
Offspring produced by parents.
Second Filial Generation (F2)
The offspring of F1.
Gene
The characteristic (i.e hair colour).
Genotype
Alleles that someone has in their genetic code.
Allele
The different types found in the gene pool (i.e red, black, brown, and blonde hair).
Phenotype
Physical expression of genetics.
Homozygous Dominant
Two dominant alleles represented by a uppercase letters (AA).
Heterozygous (Hybrid)
One dominant and one recessive allele represented by a single uppercase letter along with a sing lowercase letter (Aa).
Homozygous Recessive
Two recessive alleles represented by two lowercase letters (aa).
Mendel’s First Law - The Law of Segregation
Alleles separate randomly during gamete formation. Each gamete receives one copy of every factor.
Autosomal
“Body,” chromosomes 1-22.
Sex-Linked
Chromosome 23 (XX = genetic female; XY = genetic male).
Autosomal Dominant
A individual exhibits a dominant phenotype when they inherit at least 1 dominant allele from one parent on chromosomes 1-22.
Autosomal Recessive
A individual exhibts a recessive phenotype when they inherit 2 recessive alleles, one from each parent, on chromosomes 1-22.
Y-Chromosomes
Only genetic males with XY chromosomes inherit these genes.
➼ Genetic males have a higher probability of inheriting the recessive trait due to having one X chromosome.
Multiple Alleles
➼ Traits are typically controlled by multiple types of alleles.
➼ Heirarchy of Dominance
➼ Uppercase letters and superscript numbers are used to express a genotype.
Incomplete Dominance
When two alleles come toegher and are equally dominant, they will produce a new phenotype.
Co-dominance
Both phenotypes are fully expressed.
➼ i.e blood type (AB)
Rh Factor
➼ Along with our blood there is another antigen known as the Rhesus Factor.
➼ If an individual has the Rh antigen, then they are Rh+.
➼ If an individual does not have the Rh antigen, then they are Rh-.
➼ Rh+ is dominant over Rh-.
Mendel’s Second Law - Law of Independent Assortment
The two alleles for one gene assorts independently of the alleles for another gene.
Gene Interactions
Genes located on one chromosome can affect the expression of other genes.
Epistasis
When one gene is dependent on the presence of another.
Sex-Linked Genes
➼ Genes that are traits determined by genes located on sex-chromosomes (usually the X-Chromosome).
➼ The symbols for sex-linked traits are written with a capital X and a superscript of the letter representing the allele.
➼More recessive x-linked disorders occur in males.
Breeding Plants
➼ Corn is the result of selective breeding across many generations.
➼ Canola was developed as a alternative to rapeseed, a crop that is highly poisonous to animals.
Breeding Animals
Breeding programs are used to breed:
➼ Leaner cows
➼ Leaner Pigs.
➼ Chicken eggs with less cholestrol.
➼ Faster, strong horses.
Human Genetics
➼ Cannot do experimental breeding on humans.
➼ Too few offspring are produced to be statistically valid.
➼ Will collect family information and create a pedigree chart.
Pedigree Chart
A chart that uses symbols and finds patterns of traits in a family.
Pedigree Chart (Dominant)
➼ When observing a pedigree chart, autosomal dominant disorders are in every generation (at least in one child).
➼ If one child has the recessive phenotype, this means the parents are heterozygous for the dominant trait.
Pedigree Chart (Recessive)
➼ When building a pedigree chart, autosomal recessive traits are seen less than dominant traits.
➼ Usually seen every couple of generations (often will skip one or two).
➼ Often only one of the offspring will inherit the trait.
Sex-Linked Traits
➼ More genetic males will express the trait than genetic females.
➼ Genetic females perchance might be carriers but will not express the trait - will be passed on.
Linked Genes and Crossover
➼ Genes that are found on the same chromosome.
➼ Since they are found on the same chromosome, these traits are often found together.
Chromosome Mapping
➼ Recombination frequency - the precentage of times that a crossover occurred as the parent gametes were formed.
➼ Percentage = map unit. ➼ Farther apart the genes = larger the map unit/percentage.
