Genetic Variation Definition

Question 1

Allele Frequency

Answer 1

How often different alleles for a particular gene occur in a population

Question 2

Co-dominance

Answer 2

Where multiple alleles are expressed in the heterozygous phenotype

Question 3

Crossing Over

Answer 3

Where sections of chromosomes are exchanged during meiosis to produce new combinations of alleles

Question 4

Diploid Cells

Answer 4

Cells with a full set of chromosomes eg somatic cells

Question 5

Gametes

Answer 5

Haploid cells produced by meiosis

Question 6

Genetic Drift

Answer 6

Random changes in allele frequencies of a population due to chance

Question 7

Haploid

Answer 7

A cell with half the number of chromosomes it should have eg gametes

Question 8

Homologous Chromosomes

Answer 8

Chromosomes with the same genes in the same location but usually with different alleles, eg maternal and paternal chromosomes

Question 9

Incomplete Dominance

Answer 9

Neither allele is completely dominant so the heterozygous phenotype is a blend of the two alleles

Question 10

Independent Assortment

Answer 10

When homologous chromosomes line up during meiosis, they do so randomly, to make the combinations of chromosomes in the gametes totally random

Question 11

Linked Genes

Answer 11

Genes that are close by on the same chromosomes and will be inherited together, aka are not separated during crossing over

Question 12

Meiosis

Answer 12

Cell division to produce 4 different haploid gametes

Question 13

Migration

Answer 13

The movement of alleles from one population to another

Question 14

Multiple Alleles

Answer 14

Where some traits have more than two possible alleles

Question 15

Natural Selection

Answer 15

Individuals with advantageous traits are more likely to survive to reproductive age, and pass on those beneficial traits

Question 16

Segregation

Answer 16

Each parent’s chromatids split up randomly in the final meiosis division, so each gamete only has one random allele for each gene

Question 17

Test Cross

Answer 17

Crossing an individual with an unknown genotype with a homozygous recessive individual and analysing the phenotype ratios of the offspring

Question 18

Population bottleneck

Answer 18

An event occurs which drastically reduces population size by killing lots of individuals off - reduces genetic variation by killing off rare alleles

Question 19

Founder effect

Answer 19

Where a small proportion of a larger original population migrates to a new location - the small population won’t have the same allele frequencies as the larger population, rare alleles likely won’t be seen in the small population