Genetic Variation Flashcards
What is an allele
An allele is one or two or more versions of DNA sequence (a single base or a segment of bases) at a given genomic location
What is autosomal inheritance?
Autosomal inheritance is a way for a genetic trait or condition can be passed down from parent to child
How can you tell if genes are linked
Follow two traits between heterozygous parents and compare to Mendelian ratios.
Independent Assortment phenotypic ratio: 9:3:3:1
Linked genes phenotypic ratio: 3:1
What is incomplete dominance
A form of gene expression in which two alleles compete for dominant expression, resulting in neither phenotype being completely expressed.
What is codominance
A form of gene expression in which two alleles of a heterozygote are completely expressed to an equal degree within an organism, displaying each allele’s traits simultaneously.
What are polygenic traits
A polygenic trait is a characteristic that is influenced by two or more genes. They do not follow the patterns of Mendelian inheritance since multiple genes are involved
What is the difference between continuous and discontinuous variations
In discontinuous variations, distinct classes or categories exist which cannot be measured over a range. Individuals cannot have features that fall between categories. Meanwhile, continuous variations have a range of characteristics (such as skin colour).
What is Single Nucleotide Polymorphism (SNP)?
SNP is a variation that occurs at a single nucleotide at a specific position in the genome. They are caused by point mutations that give rise to different alleles
Why are non-coding regions more reliable to find SNPs?
Coding regions of DNA are sections of DNA that code for proteins. Even slight changes to the DNA sequence of this region can completely change the protein produced, which can have detrimental effects on the organism. This results in the organism not surviving to be able to pass on its genetic material containing the SNP which is why SNPs are less commonly found in coding regions of DNA
What are haplotypes and how do they differ from SNPs?
Haplotypes are groups of SNPs that are inherited as a single block. A SNP has at most two alleles but a haplotype block can have more than two haplotypes.
How can you find allele frequencies?
We can divide the number of copies of each allele by the total number of copies to get the allele frequency
What does the Hardy-Weinberg Principle state
“allele and genotype frequencies in a population will remain constant from generation to generation in the absence of other evolutionary influences.”
search up formula
