Genetic Variation

Question 1

genetic stability

Answer 1

passing on of consistently accurate genetic information

Question 2

genetic variation

Answer 2

occasional introduction of variation of some genetic information (mutation) allows for species adaption and increased survival in a changing environment

Question 3

effective reproduction

Answer 3

the individual reaching maturity and either sexually or asexually producing offspring

Question 4

purpose of genetic continuity

Answer 4

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

Question 5

genetic continuity - mitosis

Answer 5

• 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)

Question 6

genetic continuity - meiosis

Answer 6

• 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

Question 7

Blood groups

Answer 7

IA IA or IA Ii
IB IB or IB Ii
IA IB
Ii Ii

Question 8

non mendelian traits

Answer 8

incomplete dominance (blending of the alleles in the phenotype) 
codominance: where both alleles are expressed in their original state

Question 9

sex linked

Answer 9

traits other than those associated with sex located on the sex chromosomes

Question 10

autosomal chromosome

Answer 10

a chromosome that is not a sex chromosome

Question 11

non-autosomal chromosome

Answer 11

the sex chromosome

Question 12

Sex Linked Information

Answer 12

• 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

Question 13

Example of sex linked condition

Answer 13

• haemophilia - degeneration of the protein that causes blood clotting
• slows the clotting experience, resulting in prolonged bleeding following an injury

Question 14

population genetics

Answer 14

the study of how the gene pool of a population changes over time, leading to a species evolving

Question 15

gene pool: t

Answer 15

the sum total of all the genes and their alleles within a population

Question 16

genetic diversity:

Answer 16

the totale of all the genetic characteristics in the genetic makeup of a species

Question 17

genetic variability

Answer 17

the tendency of individual traits in a population to vary

Question 18

genetic variability

Answer 18

can be determined by analysing the relative proportion of the following within a population: phenotype, genotype, alleles

Question 19

frequency of allele G

Answer 19

number of copies of allele G in population / total number of copies of the gene (G + g) in population

Question 20

SNPs

Answer 20

singular nucleotide polymorphism

Question 21

SNP information

Answer 21

• 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

Question 22

SNPs are used for:

Answer 22

• 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.

Question 23

Conservation management:

Answer 23

use of genetic data is essential for an identifying conservation strategies to increase the chance of saving endangered species and maintaining biodiversity

Question 24

Conservation management info:

Answer 24

• 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

Question 25

haplotype (definition)

Answer 25

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

Question 26

mtDNA

Answer 26

an area of mitochondrial genome which is non-coding DNA, controls RNA and DNA synthesis

Question 27

reading a haplotype graph

Answer 27

• each proportional circle = haplotype
• lines connect each haplotype to its relative
• bars show number of mutational steps between haplotypes