L E S S O N 2

FLORAL DEVELOPMENT

Warm Up

1. When do plants normally flower?

2. What are some factors that you think plants use to decide that it is time to flower?

What was that plant from yesterday?

Had you seen the type of plant that was growing in the video from yesterday?

https://www.youtube.com/watch?v=foHiKrlY9Qc

The plant on the right has a mutation in its DNA that causes it to grow differently

Arabidopsis (Thale Cress)

• Small, fast-growing relative of broccoli, cauliflower, and mustard

• First plant genome sequenced• Small genome: only 5 pairs of

chromosomes (people have 23 pairs)

• Scientists use Arabidopsis to try to understand the biology of other plants, and even humans.

Arabidopsis (Thale Cress)

• Small, fast-growing relative of broccoli, cauliflower, and mustard

• First plant genome sequenced• Small genome: only 5 pairs of

chromosomes (people have 23 pairs)

• Scientists use Arabidopsis to try to understand the biology of other plants, and even humans.

Many experiments have already been done on

Arabidopsis!

If many scientists have been working to understand Arabidopsis for a long time… How can you find out what we have already discovered about Arabidopsis?

Araport: Google for Arabidopsis

What happens when you put “flower” into Google

What categories of information do I want?

How many results are there?

Question: What would you click here if you only wanted pictures of flowers?

What happens when you put “flower” into Araport?

Question: What would you click here if you only wanted genes that are involved in flowering?

Comparing Google and ThaleMine

If you click on any one of these categories, you will only get results of the type that you requested.

Example: if you click on “Images” in Google, you will only get picture results. If you click on “Gene” in Thalemine, you will only get gene results.

How many gene hits did we get by putting in the search term “flower?”

Finding the Mutated Gene in Araport

We can search for the gene, constans, that was mutated in the plant that we saw above, in order to see what kind of information we can find about it.

1. Enter constans into Araport. 2. Once you get the results, filter them so you only

get gene hits.

Finding the Mutated Gene in Araport

We can search for the gene, constans, that was mutated in the plant that we saw above, in order to see what kind of information we can find about it.

1. Enter constans into Araport. 2. Once you get the results, filter them so you only

get gene hits.

Finding the Mutated Gene in Araport

We can search for the gene, constans, that was mutated in the plant that we saw above, in order to see what kind of information we can find about it.

1. Enter constans into Araport. 2. Once you get the results, filter them so you only

get gene hits.

Finding the Mutated Gene in Araport

We can search for the gene, constans, that was mutated in the plant that we saw above, in order to see what kind of information we can find about it.

1. Enter constans into Araport. 2. Once you get the results, filter them so you only

get gene hits.

Finding the Mutated Gene in Araport

We can search for the gene, constans, that was mutated in the plant that we saw above, in order to see what kind of information we can find about it.

1. Enter constans into Araport. 2. Once you get the results, filter them so you only

get gene hits.

Finding the Mutated Gene in Araport

We can search for the gene, constans, that was mutated in the plant that we saw above, in order to see what kind of information we can find about it.

1. Enter constans into Araport. 2. Once you get the results, filter them so you only

get gene hits.

constans Gene page

Once you click on the constans gene page, there is A LOT of information! Let’s focus on three types of information about constans:

Genomics, Function, and Expression

Genomics: Where is this gene “written?”

Genomics shows where in the genome the constans gene is. You can scroll around to find genes that are nearby.

Genomics: Where is this gene “written?”

Genomics shows where in the genome the constans gene is. You can scroll around to find genes that are nearby.

You can also click on the gene to see its DNA code or sequence.

Genomics: Where is this gene “written?”

Genomics shows where in the genome the constans gene is. You can scroll around to find genes that are nearby.

You can also click on the gene to see its DNA code or sequence.

Function: What does this gene do?

In this section, you can look at what we think this gene actually does in the plant through brief descriptions called Gene Ontology or GO terms.

Function: What does this gene do?

Can you find any GO terms on the list that match up with what you saw in the video?

Expression: Where does this gene work?

This map shows where (and when!) the constans gene is being expressed.

This information is gathered by measuring the mRNA transcripts of the constans gene in all of the plant parts shown in the image.

What is gene expression?

What does it mean to express yourself?

A gene is encoded in DNA in the nucleus of the cell. In order for DNA’s message to be “heard” and executed in the cell, mRNA copies of the gene need to be made. How many mRNA copies of a gene that are made determines the level of gene expression.

Gene Expression Analogy

Every gene must be expressed in the right place and at the right time in order for an organism to to function well.Similarly, each member of the marching band needs to be in the right place, at the right time, and playing the right note for us to see the T Rex and hear the music.

It matters WHEN, WHERE, and HOW MUCH genes are expressed.

Would you tell someone goodnight at 9 a.m.? Would you say “congratulations” to a friend who just lost a basketball game?

It is not good for all cells in an organism to express all their genes at one time. Each type of cell has a different “expression profile that describes

What happens if genes are expressed in the wrong place, or at the wrong time?

What happens if genes are expressed in the wrong place, or at the wrong time?

When gene expression goes wrong, it’s kind of like saying the wrong thing at the wrong time. Awkward, right?

What happens if genes are expressed in the wrong place, or at the wrong time?

When gene expression goes wrong, it’s kind of like saying the wrong thing at the wrong time. Awkward, right?

*Sigh* I know what you mean, dude.

What happens if genes are expressed in the wrong place, or at the wrong time?

When gene expression goes wrong, it’s kind of like saying the wrong thing at the wrong time. Awkward, right?

*Sigh* I know what you mean, dude.

This fly has legs where its antennae should be because a gene that normally tells tissue to become legs is accidentally expressed where the antennae should be.

Expression: Where and when does this gene work?

This is a developmental map of Arabidopsis. You can see some familiar structures, like leaves and stems.

There are also some new structures, like siliques, which are like seed pods, and the shoot apex, which is where the plant grows most actively.

RED = lots of expressionYellow = little expression

IMAGE CREDITS

• https://commons.wikimedia.org/wiki/File:Small_Red_Rose.JPG• https://pixabay.com/en/tulip-flower-white-and-red-green-754304/• https://pixabay.com/en/flower-daisy-spring-766120/• https://commons.wikimedia.org/wiki/File:Jean_Giraudoux_1927.jpg• https://commons.wikimedia.org/wiki/

File:Strawberry_flower_and_guest.jpghttps://commons.wikimedia.org/wiki/File:Navionics_Strawberry_Team.jpg

• https://commons.wikimedia.org/wiki/File:Pine_Apple_Flower.jpg• https://commons.wikimedia.org/wiki/File:Honeycrisp-Apple.jpg• https://commons.wikimedia.org/wiki/File:Navionics_Pineapple_Team.jpg• https://commons.wikimedia.org/wiki/File:Banana.png• https://commons.wikimedia.org/wiki/File:BananaFlowerOcotepec.JPG• https://pixabay.com/en/flower-apple-tree-vernal-tree-93036/• https://commons.wikimedia.org/wiki/File:Arabis_thaliana_Sturm6.jpg