11/4 - crop breeding + dugga Flashcards
Varför pree breding?
All viktig info om breeding material som behövs för att sätta upp en bra breeding program
Vad är en gen?
Gene: heredlary consisting of DNA that occupies a specific location on a chromosome that encodes a specfic function product (a protein or RNA molecule) - transcribed, regulatory sequence regions
(Struktural gene: Ageneis a sequence ofDNAorRNAwhichcodesfor a molecule that has a function
(RNA emellan såklart)
Regulatory genes: Transkription factors: regulate the expression of other genes - not proteins themselves men påverkar uttrycket)
Vad är homologus cromosomer?
A couple of homologous chromosomes, or homologs, are a set of one maternal and one paternal chromosome that pair up with each other inside a cell during meiosis.
- en från mamma och en från pappan
Vad är en allell?
An allele is a variant form of a given gene.[3] Sometimes, different alleles can result in different observable phenotypic traits, such as different pigmentation. - genvariant
- Vi har 2 (mamma/papp), vete har 6
- Allo-plyploids = 3 ansesters
Utveckling: breed mellan arter kan ha lett till pollyplypoid
vad är genotyp / fenotyp
describes any observed quality of an organism, such as its morphology, development or behavior genotype describes the genetic constitution of an individual, that is the specific allelic makeup of an individual, usually with reference to a specific character under consideration
vad är locus?
A locus (plural loci) in genetics is a fixed position on a chromosome, like the position of a gene or a marker (genetic marker) - lokaliseringen av genet på kromosomen
homozygot / hetrozygot?
b) homozygote and heterozygote
Två lika aleller eller två olika aleller
A cell is said to be homozygous for a particular gene when identical alleles of the gene are present on both homologous chromosomes. The cell or organism in question is called a homozygote.
A diploid organism is heterozygous at a gene locus when its cells contain two different alleles of a gene. The cell or organism is called a heterozygote specifically for the allele in question, and therefore, heterozygosity refers to a specific genotype.
quantitative vs qualitative trait
A qualitative trait is a trait that fits into discrete categories. This means that you can neatly categorize a trait. For example, if a species of plant had either red leaves or yellow leaves, and nothing in between, this would be a discrete trait. “Yes or no” traits, traits where an organism either has the trait or doesn’t, also fit into this category. Usually, a single gene or small group of genes control qualitative traits.
Quantitative traits occur as a continuous range of variation. This means that these traits occur over a range. To picture this, imagine the length of a lizard’s tail. The length can vary, and does not fit into natural categories. Generally, a larger group of genes control qualitative traits. When multiple genes influence a trait, you can also describe it as a “polygenic trait.”
Quantitativ man mätas med exakta nr: storlek
qualitative: antingen har man det eller inte
Cromosome
broad sense heritability
Kromatider kallas de båda identiska delarna av en fördubblad kromosom som under celldelningen bildats då DNA:et i kromosomerna kopierat sig. Kromatiderna sitter i celldelningens första faser ihop med en centromer innan de två kromatiderna förs till var sin sida av cellen i celldelningens anafas.
Population
is a group of individuals of a particular specis living in a given geographic area
Kan va geografiska bariärer som gör att det inte finns något gene flow mellan populationerna innom arten
selection
Selection
Population är inom biologin (framför allt ekologin) en grupp individer av en art som finns inom ett visst område vid en viss tidn - best anpassad överlever
Fitness
- Fitness, an individual’s
ability to propagate its genes
Fitness (often denoted {\displaystyle w} w or ω in population genetics models) is the quantitative representation of natural and sexual selection within evolutionary biology. It can be defined either with respect to a genotype or to a phenotype in a given environment
genetic diversity
Genetic diversity is the total number of genetic characteristics in the genetic makeup of a species. It is distinguished from genetic variability, which describes the tendency of genetic characteristics to vary
Gen vs utseende
Phenotyp kan bero på gen och miljö
A phenotype (from Greek phainein, meaning ‘to show’, and typos, meaning ‘type’) is the composite of an organism’s observable characteristics or traits, such as its morphology, development, biochemical or physiological properties, behavior, and products of behavior (such as a bird’s nest
heritability
Heritability is a statistic used in the fields of breeding and genetics that estimates the degree of variation in a phenotypic trait in a population that is due to genetic variation between individuals in that population.[1] In other words, the concept of heritability can alternately be expressed in the form of the following question: “What is the proportion of the variation in a given trait within a population that is not explained by the environment or random chance?
Domestication
Domestication is a sustained multi-generational relationship in which one group of organisms assumes a significant degree of influence over the reproduction and care of another group to secure a more predictable supply of resources from that second group
Breeding
Breeding is sexual reproduction that produces offspring, usually animals or plants.
dominant and recessive
Dominant syns medans recesive ligger i bakgrunden
Dominance in genetics is a relationship between alleles of one gene, in which the effect on phenotype of one allele masks the contribution of a second allele at the same locus
Ärftlighet
Hur mycket genotyp påverkar fenotyp
Genetic diversety
genetic variant
Genetic diversety = antal alleler
genetic variant = calculate hur common en alell är I en population
Broad sense heritability
Broad sense heritability 's the proportion of phenotypic variance in a population that is attributable to genetic variance among individuals
Genetic diversity och Genetic variation
Genetic diversity : number of alleles within
a population
Genetic variation: Allele frequencies within
and between populations
Subpopulation
Subpopulation — a geoogrephically isolated group of individuals which can mate and
produce offspring. They are sharing the same gene pool (a complete set of allees
and the sum of all genotypes in the subpopulation)
Polymorfism
Polymorfism — The occurrence of more than one allele at the same locus with the least
frequent allele occurring more frequently than can be accounted for by mutation alone
What causes changes in genetic variation?
Migration/ gene flow
Increases variation within populations,
decreases variation among populations
Selection - Homoqenous habitat - decreases variation within populations - Heteroqenous habitat(s) increases variation within and among populations
Genetic drift
Decreases variation within smal/ populations,
increases variation among populations
(genetic differentiation)
Gene drift
Genetic drift — loss of genetic variation
Founder and bottteneck effects
Founder and bottteneck effects — situations
where genetic drift Will have a major effect on
the genetic variation in a population
När började vi att faktiskt breed växter
iinte så länge sen - 200år sen, vi domesticerade mest utan att va medvetna om generna (1200år sen )
Modern plant breeding använder sig av
Modern plant breeding - uses molecular genetic techniques to select (marker- assisted selection) or in the case of genetic modification — gene expression may be changed of targeted / desirable genes or genes may be transfered within and across species-
Vad är traditional plant breeding`?
Ta de med fenotypen man vill ha och fårtsätter i samma stil
steg 1) Crossing of selected
genotypes
steg 2) Selection of progenies
with desirable traits by
phenotypic (field)
evaluation - tillbaka till steg 1
Marker-assisted plant breeding
steg 1) Crossing of selected
genotypes
steg 2) Selection oi progenies with desirable traits combining phenotypic (field) and genetic evaluation - till steg 1
Stoppa in en marker och kolla om den finns sen i offspring (tror jag)
Genetic modificatjon in plant breeding
Gene modification Transforming single genes, e.g -Bt-crops (Bacillus thurengiensis — insectresistans -Roundup-ready-crops — (bacteria) herbicide resistance -"Golden rice" (narciss+bacteria), betacarotene -MiEdew resistance in potato (wild relative)
Stoppa in ny gen
Crossing of selected
modified
genotypes/phenotypes
När var devanliga cropsen domesticereade?
500 domesticated plants of which about 100 is considered important.
Most of them were domesticated for more than 4000 years ago,
Hur evolvas crops?
Wild plant pop
- Phenotypic changes (morphological and fysiological)
- GenetiG changes
Human selection + Natural selection gives
Crops
- Totaly dependent c uman
Human selection + natural selection gives:
New crop and cultivars
Vilka är de vanligaste morfologiska changes in the crop mellan wild type?
Loss of seed dispersal - seed stannar kvar så lättare att harvest
Larger fruits, grains and tubers
Change in inflorescence structure
appical dominance
shift to perenial to annual
loss of seed dornamcy
self polination
sunkroniserad flowering
adopterade till photoperioden
Vad sker vid breeding mot specefika egenskaper
loss of genetic diversety
rare gene - specefik typ av gen 5/6 är TF
Vad är neutral gene och selected gene
- skillnader
bra bild i pp
natural gene - större hål i tratten och släpper igenom fler olika
selected gene - mindre hål - släpper bara igenom de med den gen man vill ha
Genes changed as a result of domestication — regulatory genes
- Larger fruits
- Loss of seed dispersal
- Change in- inflorescence structure - större ätdelar som - ej är frukt
- Apical dominance
Varför har man på vissa växter odlat bort stop kodon?
Inget stopp för att sluta växa - tex större calicoflower
Vad är lite dåligt med att få mer nerslimade cultivarer som alla ser lika dana ut
Förlorar andra gener som kanske hade varit bra att ha - mindre rötter ges som exempel
Vad är top-up vs bottom down?
top-down: fenotype till signature of adoptation
(kollar på utseende och går sen ner och kollar vilka gener det är)
down-top: signature of adaption till fenotype
(går från generna och kollar sedan på fenotypen)
Båda görs för att kolla hur det hänger ihop
TF
Transkriptionsfaktorer är proteiner som på något sätt, direkt eller indirekt, är involverade i transkriptionen av gener.
