Week 1 Online Module 1 Flashcards
What is genetics?
Genetics is the study of hereditary and the variation of inherited characteristics. It seeks to understand the transmission of genetic material from:
parent to offspring (transmission genetics), from DNA to function (molecular - development genetics) and over many generations within the population (population genetics)
What are genes?
Genes influence the expression of traits. Each human has between 20,000 and 25,000 genes (sections of DNA). this collection is called a genome. this determines a humans traits at a cellular level. Chromosomes carry this genetic information in the cell’s nucleus in the form of DNA.
what is the difference between genotype and phenotype?
A genotype is the genetic makeup of an individual
The phenotype is the observable characteristics or traits
The wildtype is the most common variety observed and variants that differ from the wildtype are called mutants
polymorphisms are when there are two or more common phenotypes like apple colours
what do P, F1 and F2 stand for?
P for Parental generation
F1 for first filial generation
F2 for second filial generation
What does pure breeding mean?
Pure breeding means that all offspring produced by mating from this line are identical
What is mendel’s law of equal segregation?
- A hereditary gene is necessary for producing pea colour
- Each plant has a pair of this type of gene
- The gene comes in two forms called alleles (for example, Y and y) Alleles are versions of the same gene which are generally identical but which differ in >1 nucleotide.
- A plant can be either Y/Y (homozygous dominant), y/y (homozygous recessive) or Y/y (heterozygous)
- In the Y/y plant, the Y allele dominates so the phenotype is yellow. The phenotype of the Y/y plant defines the Y allele as dominant and the y allele as recessive.
- In meiosis, the members of a gene pair separate equally.
- At fertilization, gametes fuse randomly (gametes is when a haploid cell that fuses with another haploid cell during fertilization (conception) in organisms that sexually reproduce)›
When a monohybrid is testcrossed
a 1:1 phenotypic ratio is expected
When a monohybrid is selfed
a 3:1 phenotypic ratio is expected
Autosomal Recessive Disorders appear
in the progeny of unaffected parents and affects males and females. you won’t see it passed down in all generations
Autosomal Dominant Disorders appear
affected fathers or mothers transmit the genotype to both sons and daughters and the disorder appears in every generation
