The Evolution of Genes and Genomes

Germ line

the cell lineage in a multicellular organism that contributes to the formation of the nextgeneration by producing gametes (sperm or eggs)

Somatic cell

any cell in a multicellular organism that is not a germ line cell

the mutation may affect the individual in which the mutation occurred

If the mutation appears in the somatic cell...

the mutation will not affect the individual but may be passed to the next generation and may result in a heritable trait

If the mutation appears in a germ cell, after the germ line is set aside...

regulatory DNA

Related genes may take very differet developmental pathways due to differences in the...

ectopic expression

what type of expression occurs in drosophila when the Antennapedia gene in the head due to a mutation in its regulatory DNA

regulatory DNA of the lactase gene

The ability to digest lactose is due to a mutaion in the...

allows the enzyme to be made beyond infancy

what does the mutation that gives the ability to digest lactose allow for?

Northern Europe and Central Africa

where is the lactose mutation generally selected for?

gene families

groups of genes that originate from a common ancestral gene that are grouped by similarities in structure and/or function

globin gene family

an example of a gene family

subunits of hemoglobin

the genes of the globin gene family code for...

3 exons and 2 introns

the structure of the subunits of hemoglobin

fetal, embryonic, and adult stages

what stages have different hemoglobin versions?

pseudogenes

non-functioning genes

alpha and beta units

what does the adult versions of the hemoglobin subunits contain?

chromosome 16

where is the alpha globin located?

chromosome 11

where is the beta globin located?

higher

embryonic and fetal globins have ________ affinities for oxygen than adult globins

gene duplications

gene families originate by...

misalignments and unequal crossing over

short repeated sequences within homologous chromosomes may cause...

unequal crossing over

results in chromosomes with altered sizes and genetic contents

transposition of mobile genetic elements

can meidate the recombination of genes or regulatory sequences

the transposition mechanism may use the ends of the 2 different elements, resulting in the movement of the entire segment of the chromosomes between them

If two similar mobile genetic elements happen to be inserted near each other in a chromosome...

tissue-specific

the transposition of regulatory sequences can alter the _________ pattern of expression of genes

ends of the 2 different elements

If 2 similar mobile genetic elements happen to insert near each other in a chromosome, the transposition mechanism may use the...

using the 2 ends of a single mobile element

what would result in the transposition of just one element?

the transposition of the entire segement of the chromosome between the two mobile elements

the result of using the ends of 2 different elements

its insertion into a second gene would create a new version of that gene

If the transposed segment includes an exon...

Exon shuffling

the duplication and movement of segments of DNA can result in the origin of new proteins by piecing together fragments of different genes

new proteins with multiple functional domains

the result of exon shuffling

vertical transfer

from parent to progeny through gametes

horizontal transfer

from one organism to another

viral infections

conjugations

2 examples of horizontal transfer

conjugation (sex between bacteria)

the transfer of DNA from one bacterium to another through a sex pilus

genetic recombination without reproduction

what is conjugation an example of?

Amyotrophic lateral schlerosis

a progressive neurodegenerative disease that affects nerve cells in the brain and spinal cord

an ancient virus that has become activated in certain individuals causing ALS

what is believed to be the cause of ALS?

HERVs

retroviruses that infect neurons and germ cells that have been linked to ALS