Genetic Variation Flashcards
genetic stability
passing on of consistently accurate genetic information
genetic variation
occasional introduction of variation of some genetic information (mutation) allows for species adaption and increased survival in a changing environment
effective reproduction
the individual reaching maturity and either sexually or asexually producing offspring
purpose of genetic continuity
Purpose of genetic continuity: to ensure continuation of a species, because it ensures that new cells of organisms have all the genes they need, in working order, to survive. A lack of genetic continuity results in death or disease. Genetic continuity is dependent on: mitosis, meiosis
genetic continuity - mitosis
- Mitosis: two daughter cells must have the same number and types of genes as the original cell in the case it doesn’t occur correctly – this could be detrimental to the survival of the organism.
o Key Process:
o DNA replication including the proofing and repairing of mistakes (polymerase)
o Chromosome duplication to form two chromatids, joined by centromere
o Chromatids faithfully separating into different daughter cells (cytokinesis ensuring both daughter cells are viable)
genetic continuity - meiosis
- Meiosis: the resulting offspring must have the same number of genes as the parent organism
o Key Processes:
o Crossing over of paired chromatids, exchanging genes and DNA along chromosome
o Random and independent segregation of chromosomes
o Halving of the number of chromosomes in the first reduction division to allow fertilisation of gametes
Blood groups
IA IA or IA Ii
IB IB or IB Ii
IA IB
Ii Ii
non mendelian traits
incomplete dominance (blending of the alleles in the phenotype) codominance: where both alleles are expressed in their original state
sex linked
traits other than those associated with sex located on the sex chromosomes
autosomal chromosome
a chromosome that is not a sex chromosome
non-autosomal chromosome
the sex chromosome
Sex Linked Information
- most likely found on the X chromosome (larger, contains more genes)
- annotated: affected = X^h X^h or X^h Y
- males are more likely to express a sex-linked recessive condition because the altered copy of the gene only has to occur to one X chromosome in each cell
Example of sex linked condition
- haemophilia - degeneration of the protein that causes blood clotting
- slows the clotting experience, resulting in prolonged bleeding following an injury
population genetics
the study of how the gene pool of a population changes over time, leading to a species evolving
gene pool: t
the sum total of all the genes and their alleles within a population
genetic diversity:
the totale of all the genetic characteristics in the genetic makeup of a species
genetic variability
the tendency of individual traits in a population to vary
genetic variability
can be determined by analysing the relative proportion of the following within a population: phenotype, genotype, alleles
frequency of allele G
number of copies of allele G in population / total number of copies of the gene (G + g) in population
SNPs
singular nucleotide polymorphism
SNP information
- occurs during DNA replication, a mutation occurs (missed by polymerase)
- for a mutation to be a SNP, at least 1% of population has to havce it
SNPs are used for:
- Use of SNPs for conservation management, determination of the inheritance of a disease / diosrder, study of human evolution
- SNPs are used as biological markers, helping scientists locate genes that correlate with diseases. They help predict an individual’s response to drugs, susceptibility to environmental factors such as toxins and risk of developing particular disease. Can also be used to track inheritance of disease.
Conservation management:
use of genetic data is essential for an identifying conservation strategies to increase the chance of saving endangered species and maintaining biodiversity
Conservation management info:
- used to identify segments of genome essential for an organism’s adaptation to the environment
- can determine relationships and identify individuals that could be reintroduced into a population for recovery
- detects any harmful mutations that may affect function
haplotype (definition)
a group of genes found on the same chromosome which are inherited together. it is specifically a group of SNP markers inherited from the mother’s lineage as mitochondrial DNA
mtDNA
an area of mitochondrial genome which is non-coding DNA, controls RNA and DNA synthesis
reading a haplotype graph
- each proportional circle = haplotype
- lines connect each haplotype to its relative
- bars show number of mutational steps between haplotypes
