BIO220 (Genomes to Ecosystems) - Lecture 1, Week 2

What are the three agricultural species that comprise 60% of energy intake in Homo sapiens?

Rice, maize, and wheat

Where can you find the ancestral relatives of domesticated species?

The region where their ancestral species were first domesticated

Ancestral relatives of domesticated species have greater [blank] [blank]

Genetic diversity

What are the two selective forces that occur during domestication?

Bottleneck, and artificial selection

Definition of bottleneck

When a limited number of individuals within a population contribute their genetic material to the subsequent generation

Definition of artificial selection

The process where humans intentionally select certain individuals (i.e., individual within desired phenotypes) within a population to contribute to their genetic material to the subsequent generation

Artificial selection and bottlenecks result in [blank] [blank] within a population

Genetic variation

Where is genetic variation absent in the genome of domesticated species?

The are of the genome that produces favourable phenotypes

What are that three way as to measure genetic variation?

1. Proportion of individual with heterozygosity per gene locus

2. Proportion of polymorphic gene loci

3. Average number of nucleoside differences per region of genome

Definition of effective population size (Ne)

Idealized population that loses genetic diversity with respect to the observed population (i.e., the number of reproductively active individuals within a population)

Definition of idealized

All individuals within a population have equal opportunity to contribute their genetic material to the subsequent generation

Definition of census size (N)

Total number of matured individuals within a population

The effective size of a population is [great than/less than] census size

Less than

What are the four factors the contribute to effective population size being lesser than census size?

1. Variation in number of progeny one reproductively active individuals within the population produces

2. Unequal sex ratio (i.e., number of reproductively active males outnumber the number of reproductively active females within the population)

3. Progeny mating with parents

4. General fluctuations in the number of individuals within a population (e.g., population bottleneck)

Reduced effective population size happens in the [blank] and [blank] of selection

Presence and absence

How do the presence of selective forces (e.g., natural selection or artificial selection) influence effective population size?

Reduces the effective population size

Describe what information is communicated in the figure below.

Left figure: Population bottleneck produces a reduction in the effective population size across all loci within the genome

Right: Artificial selection produce a greater reduction in the effective population size in locus-specific regions within the genome

What percentage of the teosinte genome experienced artificial selection?

2-4%