BIO 107 (Principles of Genetics: Plant Genetics and Crop Biodiversity)

Plant Genetic Resources

Genotypes of particular species, collected from different sources and geographical origins, for use in plant breeding to develop new cultivars

Germplasm of a crop

the sum total of hereditary material

Plant Genetics

The study of genes, genetic variation, and heredity in plants is known ___________

crop breeding, conservation of plant genetic diversity

Understanding the principles of plant genetics may be important in many activities involving __________ and __________

Gregor Mendel

__________ looked into "trait inheritance," or how qualities are passed down from parents to offspring.

trait inheritance

how qualities are passed down from parents to offspring

gene

unit of inheritance

gene

fundamental physical and functional units of inheritance

gene

essentially segments of the molecule DNA

gene

the chemical sequence of which is ultimately responsible for producing all growth and development processes of an organism

locus (plural: loci)

Particular genes usually occur at a specific location, referred to as a __________, on chromosomes.

chromosomes

the threadlike DNA and protein-based structures in cells whose function is the orderly duplication and distribution of genes during cell division

morphology, descending order

pair of chromosomes were arranged according to their __________ and numbered according to their length in __________

32

Alfalfa

Medicago sativa

24

Avocado

Persea americana

14

Barley

Hordeum vulgare

36

Bermuda grass

Cynodon dactylon

12

Broad bean

Vicia faba

42

Cashew

Anacardium occidentale

20

Corn (maize)

Zea mays

52

Cotton, American-Egyptian

Gossypium barbadense

52

Cotton, upland

Gossypium hirsutum

56

Durian

Durio zibethinus

30

Flax

Linum usitassimum

14

Garden pea

Pisum sativum

38

Grape

Vitis vinifera

22

Guava

Psidium guajava

22

Kidney bean

Phaseolus vulgaris

40

Mango

Mangifera indica

42

Oats, white

Avena sativa

42

Oats, red

Avena byzantina

16

Onion

Allium cepa

18

Papaya

Carica papaya

40

Peanut

Arachis hypogaea

50

Pineapple

Ananas comosus

48

Potato

Solanum tuberosum

24

Rice

Oryza sativa

14

Rye

Secale cereale

20

Sorghum

Sorghum vulgare

40

Soybean

Glycine max

40

Squash

Cucurbita pepo

18

Sugar beet

Beta vulgaris

80

Sugar cane

Saccharum officinarum

24

Tamarind

Tamarindus indica

48

Tobacco

Nicotiana tabacum

24

Tomato

Lycopersicum esculentum

28

Wheat, durum

Triticum durum

42

Wheat, common

Triticum vulgare

42

Wheat, club

Triticum compactum

genome

the total chromosomal DNA of an organism is referred to as its __________ with each set of chromosomes making up a single genome

two, parent

A diploid organism, therefore, has __________ genomes, one from each ___________.

genome

the total chromosomal DNA of a species

haploid

they contain half the number of chromosomes of a diploid cell

allele

The specific composition of DNA at each gene

True.

True or False:

Alleles may differ between chromosomes in a diploid species or among chromosomes in polyploid species

mutations

Multiple alleles of a gene may be generated by __________.

mutations

structural or chemical changes in DNA

Genetic variation (diversity)

the result of differences among individuals in a group

Genetic variation (diversity)

a function of allelic differences resulting from mutations, and the random assortment of alleles during meiosis

Meiosis

a special type of cell division that ultimately leads to the production of sperm and egg.

genotype

An individual’s ___________ is the set of alleles it possesses at a certain locus or over particular loci

False.

can be expanded

True or False:

Genotype can not be expanded to reflect allelic constitution over all of the loci in the individual.

phenotype

the appearance or performance of an individual

heterozygous

If different alleles exist at a locus in an individual, the locus is considered __________

heterozygote

If different alleles exist at a locus in an individual, the individual/organism is considered ___________

homozygous

If alleles at a locus are the same, the locus is ___________

homozygote

If alleles at a locus are the same, the individual/organism is ___________

morphological markers

How is assessment of genotype done?

morphological markers

an easily observable genetically determined trait that identifies, or marks, different genotypes

True

True or False:

Although morphological markers are generally easy to use, their usefulness is limited by their availability

molecular markers

identify differences in the genetic code (DNA) among individuals

DNA fingerprinting

The process of using molecular markers to identify individuals is known commonly as ___________

restriction endonucleases

Plant DNA is segmented by certain enzymes called ____________

False.

different

True or False:

S endonucleases recognize same segments of the DNA code.

cut

When a particular endonuclease finds its DNA code segment in the plant DNA, it makes a __________

fragments, gel electrophoresis

After the DNA has been cut, the DNA segments, now called __________, are separated by ___________

electrophoresis

separates the fragments by size with the largest fragment appearing at the top of the gel and successively smaller fragments

stain

A ___________ is added to the gel that reacts with the DNA fragments causing the DNA to become visible.

sexual

Plant species exhibit great variability in __________ reproduction and this has significant effects on the genetic constitution of individuals, specially the average heterozygosity or homozygosity that they possess.

complete self-pollination, complete cross-pollination

reproduction may range from _____________ to ____________

complete self-pollination

reproduction where seeds are derived from pollen that has come only from the same plant

complete cross-pollination

reproduction where pollen that leads to seed is received only from different plants.

highly homozygous

Individuals in self-pollinated species tend to be ___________

repeated self-pollination

When heterozygosity does occur in self-pollinated species, either as a result of mutation or cross-pollination between genetically different individuals, ___________ tends to rapidly reduce the amount of heterozygosity present within offspring of a given individual

heterozygosity, sexual

in species that tend to exhibit more cross-pollination, ___________ is typically much more common and is generally preserved over generations of ___________ reproduction.

sunflower, rose

More than 400 plant species, including many grasses and members of the _________ and __________ families exhibit apomixis

apoximis

an asexual reproductive process where seeds are not derived from the union of sperm and egg (fertilization) but result from the development of a body cell into an embryo

equal

Plants derived from seeds produced by means of apomixis are genetically __________ to the parental plant that produced them.

False.

large areas

True or False:

In apomictic species, a single genotype may occupy very small areas and therefore populations may contain relatively little genetic variation.

inbreeding

results from matings between individuals that are related to each other and therefore possess alleles derived from a common ancestor(s).

self-pollination

the most extreme example of mating between individuals that are related to each other

inbreeding

cross-pollination between other kinds of relatives will also lead to ____________.

inbreeding depression

In many cross-pollinated species, inbreeding may lead to an overall decline in plant performance that is known as ____________

self-pollinated

Species that are predominately ___________ typically do not display significant inbreeding depression.

heterosis or hybrid vigor

the opposite of inbreeding depression

heterosis or hybrid vigor

observed when the performance of offspring from a mating far exceeds that of the parents

highly heterozygous

heterosis is observed in offspring produced from matings between 2 genetically different parents that will tend to produce ___________ offspring

evolution

Genetic variation that exists among plants within and among populations is ultimately due to actions of __________.

evolution

a collection of processes that results in a change in allele frequencies over time.

many

In a high CO2 environment, an individual with few stomata produces ___________ offspring