5.4

Question 1

what is the significance of crossing over?

Answer 1

creates new allele combinations which add diversity to the gene pool of the population
o The four gametes formed in meiosis will not be identical but rather can have different alleles for each gene.
This therefore increases genetic variation in a population and can introduce new phenotypes that potentially* could be expressed.

Question 1

what is the significance of fertilisation in predicting variations in offspring

Answer 1

further increases the shuffling of genetic material and increases the possibility of variation arising
For this reason siblings always differ from each other either slightly or significantly.

Question 2

what is the significance of independent assortment and random segregation inregard to potential variations

Answer 2

two independent assortment and random segregation introduce (genetic) variation into the alleles that each gamete inherit after Cytokinesis II in Telophase

Question 3

differentiate between sister chromatids and non sister chromatid?

Answer 3

same chromosome or not

Question 4

• If the organism has two dominant allele for a particular gene, the __________ allele will be expressed.

Answer 4

dominant

Question 5

• If the organism has two alleles for a particular gene, one dominant and the other is recessive, the _________ allele will be expressed.

Answer 5

dominant

Question 6

• If the organism has two recessive alleles for a particular gene, the ? allele will be expressed.

Answer 6

recessive

Question 7

what are autosomes?

Answer 7

An autosome is a chromosome in an organism that is not a sex chromosome.

Question 8

what is the mendel method

Answer 8

Mendel crossed a pure breeding tall plant (BB) with a pure breeding short plant. He created two laws of biology based on such information which still applies today.

Question 9

what does the first law of dominance and segregation state

Answer 9

The characteristics of an organism are determined by factors that occur in pairs. Only one member of a pair of factors can be represented in any gamete (segregation). Offspring inherit one factor from each parent. This shows 3:1 overpower.

Question 10

what is the second law of sorting

Answer 10

Mendel’s second law relates to how variation arises in meiosis

In this law, he established further ratios showing that when individuals with two or more pairs of unrelated, contrasting characteristics are crossed (for example, tall plants with yellow pods × short plants with green pods), the different pairs of factors (tall/short and yellow/green) separate out independently of each other

Question 11

what is autosomal inheritance?

Answer 11

• The process of transferring genes (DNA) present in the parents’ autosomes to offspring is called autosomal inheritance.
• If it is a 50/50 ratio between men and women the disorder is autosomal
• Autosomal dominant inheritance : The dominant alleles take over the recessive
• Autosomal recessive inheritance : the recessive alleles manage to be dominant

Question 12

what is co-dominance?

Answer 12

When two different alleles for the same gene are present and both are expressed as separate, unblended phenotypes.
* equally dominant and both expressed

-cow have both brown and white colour pathes on its skin

Question 13

what is incomplete dominance

Answer 13

When one allele of a gene is not completely dominant upon another allele of the same gene, then the phenomenon is known as incomplete dominance.

• snapdragon flower

Question 14

what is sex linked inheritance

Answer 14

Sex chromosomes carry genes that determine the sexual characteristics of a person and therefore influence whether they are male or female

Females have a pair of sex chromosomes XX, males being XY, with y being shorter and therefore not carrying a sex-linked gene

Question 15

what are multiple alleles

Answer 15

In cases of multiple alleles, there are more than two alleles that exist for a particular gene.
However, only TWO ALLELES may be present in any individual at a single locus

Question 16

what is the use of a pedigree

Answer 16

A pedigree chart can be used to record phenotypes and work out the genotypes of a family, in order to study hereditary patterns, mutations that result in diseases and predict for future offspring

• Determine inheritance patterns
• Assign genotypes to individuals where possible
• Make predictions about the risk/probability of an individual inheriting a trait

Question 17

in a pedigree a cirlce and square refer too»

Answer 17

differing genders : circle being women square being men

Question 18

what is a diamond used for in a pedigree

Answer 18

unknown gender : unborn baby

Question 19

what does a shaded circle indicate in a pedigree

Answer 19

has the affected trait

Question 20

what does a half shade indicate in a pedigree

Answer 20

a carrier of the disease/trait

Question 21

what r the 4 characteristics present in an autosomal domanince pedigree

Answer 21

• equal chance of appearing in both genders
• trait cannot skip a generation row
• affected can either have one or two parents affected
• heterozygous parents express the dominant trait can have an unaffected offspring

Question 22

what r the 4 characteristics present in an autosomal recessive inheritance

Answer 22

• the trait has equal chance to appear
• trait can usually skip a row
• • If both parents expresses the recessive trait, all of the offspring must express the recessive trait.
• • Affected offspring expressing the recessive trait could have two unaffected heterozygous parents

Question 23

what are the 4 characteristics presentin a sex linked dominance pedigree

Answer 23

• affected father will pass his x linked trait to his daughter but not son
• mother- father/mom (either)- if father the daughter will get it
• trait CANNOT be skipped in a row
• expressed more in females then males

Question 24

what r 4 characteristics that are present in sex linked recessive inheritance pedigrees

Answer 24

-affected father will give trait to his daughter but no son -if mother is affected, all sons are affected -trait can skip a row -if mother is a carrier n father isnt affected, the son will have a 50% chance to be affected n daughter will not be affected -if mother carrier and father affected all kids have an equal chance of getting it

Question 25

what is population genetics?

Answer 25

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

Question 26

what is the purpose of population genetics?

Answer 26

* combines mendelian genetics and Darwinian evolution to explain how changes in allele frequencies arise and how they can lead to microevolution and macroevolution * scientists measure the degree of genetic variation in a population overtime to make predictions about how populations adapt to their environments and which populations are most likely to evolve or die out.

Question 27

how to get the allele frequency

Answer 27

number of copies of alleles (g) in a population/ total number of copies of gene (G+ g) in population

Question 28

how to get the genotypic frequency?

Answer 28

number of particular genotype./ total number of genotype in a population

Question 29

how to find the phenotypic frequency

Answer 29

number of particular phenotype in a population/total number of phenotypes in a population

Question 30

why collecting data is important?

Answer 30

gathering quantitative data and applying abstract mathematical model predict how external factors influence frequencies such as bottleneck effect or a founder effect

Question 31

why is data limited in regard to phenotypes and sampling?

Answer 31

* Phenotypes do not always indicate genotype * Sampling may not include a sufficient sample size * Sampling may be insufficient to reflect the whole population gene frequency

Question 32

what is the hardy-weinberg principle

Answer 32

* mathematical model that calculates allele frequency of traits with dominant and recessive alleles * calculate allele frequency of a gene in the population to show changes in frequency overtime p^2+2pq+q^2=1

Question 33

what is genetic drift?

Answer 33

* Random changes in allele frequency from one generation to another * In a large population = has a small effect on population/little impact on genetic diversity and evolution * Small population = genetic drift has a large effect on genetic diversity and evolution

Question 34

what are single nucleotide polymorphisms?

Answer 34

Single nucleotide polymorphism is where one nucleotide in the genome of an individual is different to the rest of the population’s nucleotide at the same location in the DNA or gene. This is because, due to SNP, a new nucleotide randomly replaces or substitutes an existing nucleotide in the organism’s DNA sequence.

Question 35

For a change in DNA sequence to be considered a SNP, the same SNP must be experienced by organisms in at least......

Answer 35

1% or more of the species' population. if not the change is deemed a mutation.

Question 36

99% of all SNPs events occur...

Answer 36

outside the coding region of the dna responsible for specifying for a protein (non-coding_ outside the coding region of DNA will NOT have a direct effect on the organism’s ability to function normally as the majority of SNPs mainly occur in the non-coding areas of the DNA as they dont specify for a protein.

Question 37

what are the two groups in coding snps

Answer 37

non-synonymous and synonymous

Question 38

differentiate between non-synonymous and synonymous snps

Answer 38

in synonymous, the protein structure and function will NOT be affected in non-synonymous, the change in codon sequence will alter the chain in amino acids. there r two types mis sense which will specify a differeny amino acid and non sense where the stop codon will occur at the wrong time.

Question 39

what is the importance of collecting data using technology in SNPs

Answer 39

SNPs can have an effect on altering the physical, physiological and even behavioural traits (e.g. personality) or characteristics of an organism. Genome-wide association studies (GWAS) employs computer technologies to obtains a detailed report on the genome of individuals. Researchers scan the sections of DNA that have the greatest variance amongst species the population and documenting the SNPs of the scanned individuals. By obtaining genome reports of individuals with and without a trait (or with and without disease) in the population, scientists can attempt to determine the genes that are responsible for certain traits or diseases. This is done by comparing the frequency of SNPs that appear between an affected individual and an unaffected individual. the higher the frequency of SNPs, the more likely those SNPs are related to the trait or disease the affected individual has developed.

Question 40

what are limitations in regard to collecting data on SNP's

Answer 40

* Technology can never prove that it is 100% SNP’s effect o scientists would still require taking into account of the environment factors that may contribute to an individual developing the trait (or disease) of concern. * Diseases can also be monogenic or multigenic. Monogenic are caused by one ‘faulty’ gene whereas multigenic is caused by multiple ‘faulty’ gene.

Question 41

the greater the genetic diversity a population has.....

Answer 41

the more capable it is able to adapt to changing selective pressures in the environment which the species residues in.