Genomes and Their Evolution

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11

of FOXP2 disrupted

Homozygote: both copies

of FOXP2 disrupted

Experiment 2: Researchers separated each newborn pup

from its mother and recorded the number of ultrasonic

whistles produced by the pup.

Experiment 2

Number of whistles

(No

whistles)

Wild

type

Hetero-

zygote

Homo-

zygote

400

300

200

100

0

Slide 79

Comparing Genomes Within a Species

As a species, humans have only been around about 200,000 years and have low within-species genetic variation

Variation within humans is due to single nucleotide polymorphisms, inversions, deletions, and duplications

These variations are useful for studying human evolution and human health

Slide 80

Comparing Developmental Processes

Evolutionary developmental biology, or evo-devo, is the study of the evolution of developmental processes in multicellular organisms

Genomic information shows that minor differences in gene sequence or regulation can result in major differences in form

Slide 81

Widespread Conservation of Developmental Genes Among Animals

Molecular analysis of the homeotic genes in Drosophila has shown that they all include a sequence called a homeobox

An identical or very similar nucleotide sequence has been discovered in the homeotic genes of both vertebrates and invertebrates

Homeobox genes code for a domain that allows a protein to bind to DNA and to function as a transcription regulator

Homeotic genes in animals are called Hox genes

Slide 82

Fig. 21-17

Adult

fruit fly

Fruit fly embryo

(10 hours)

Fly

chromosome

Mouse

chromosomes

Mouse embryo

(12 days)

Adult mouse

Slide 83

Fig. 21-17a

Adult

fruit fly

Fruit fly embryo

(10 hours)

Fly

chromosome

Slide 84

Fig. 21-17b

Mouse

chromosomes

Mouse embryo

(12 days)

Adult mouse

Slide 85

Related homeobox sequences have been found in regulatory genes of yeasts, plants, and even prokaryotes

In addition to homeotic genes, many other developmental genes are highly conserved from species to species

Slide 86

Fig. 21-18

Thorax

Genital

segments

Thorax

Abdomen