* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Keywords - NCEA Level 2 Biology
Epigenetics of neurodegenerative diseases wikipedia , lookup
Oncogenomics wikipedia , lookup
Genetic drift wikipedia , lookup
Pharmacogenomics wikipedia , lookup
Polymorphism (biology) wikipedia , lookup
Genetic engineering wikipedia , lookup
Point mutation wikipedia , lookup
Human genetic variation wikipedia , lookup
Behavioural genetics wikipedia , lookup
Gene desert wikipedia , lookup
Pathogenomics wikipedia , lookup
Skewed X-inactivation wikipedia , lookup
Heritability of IQ wikipedia , lookup
Essential gene wikipedia , lookup
Public health genomics wikipedia , lookup
Neocentromere wikipedia , lookup
Dominance (genetics) wikipedia , lookup
Site-specific recombinase technology wikipedia , lookup
Polycomb Group Proteins and Cancer wikipedia , lookup
Population genetics wikipedia , lookup
History of genetic engineering wikipedia , lookup
Nutriepigenomics wikipedia , lookup
Y chromosome wikipedia , lookup
Genome evolution wikipedia , lookup
Gene expression programming wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Minimal genome wikipedia , lookup
Ridge (biology) wikipedia , lookup
Quantitative trait locus wikipedia , lookup
X-inactivation wikipedia , lookup
Genomic imprinting wikipedia , lookup
Gene expression profiling wikipedia , lookup
Epigenetics of human development wikipedia , lookup
Biology and consumer behaviour wikipedia , lookup
Designer baby wikipedia , lookup
Keywords Independent assortment: Alleles of genes on nonhomologous chromosomes assort independently during gamete formation. Segregation: The two alleles for each gene (on homologous chromosomes) separate during gamete formation. Linkage: Genes which are carried on the same chromosomes tend to be inherited together. Crossing over may separate linked genes. Chromosome map: Shows the genes on one chromosome and how close together they are. Which is the odd one out and why? Independent Assortment Chromatid Crossing Over Chromosome mutation 6. Linked genes and gene maps SC: Explain how linkage may affect phenotypes shown in offspring Describe what is shown by a gene map. Mutations pg 93 Benefici al / Harmful Where, when , how? Sources of variation Reproduction Population Genetics pg 123 Pg 109 Using monohybrid crosses Lethal alleles pg 110 Linkage pg 103 Genetic Variation and Change Mendelian Genetics Incomplete dominance pg 109 Sexual Gene Pools pg 92 Genetics Tool Box – Intro. Changes to allele frequencies Using dihybrid crosses pg 113 Codominan ce pg 109 Multiple alleles pg 110 Segrega -tion pg 99 Independ ent assortment pg 101 Crossing over pg 102 Linkage pg 118 Independent assortmen t pg 114 Genetic Drift pg 126 Migratio n pg 126 Natural selectio n pg 132 Independant assortment recap In Labradors black(B) is dominant to brown coat(b) and blindness (n) is recessive to normal vision (N). As these two genes are on different chromosomes they move independently into gametes depending on how they line up along the equator. If two dogs were bred which were heterozygous for each trait what possible gametes could form? What percentage of each gamete should form? Did you know? The number of genetic variations possible in our sperm and eggs thanks to independent assortment is 223 or 8388608 – that is before we add in variation due to crossing over or mutation. Linked genes Are genes which are on the same chromosome. They do not show independent assortment unlike genes on different chromosomes. During Anaphase two, these genes travel to the same gamete together. Linked genes have different phenotype ratios in gametes than genes on different chromosomes. Linked genes only become separated if crossing over occurs between the two gene locii. Gene Maps Tell us three things… 1. What genes are linked 2. What genes are on the chromosome 3. How close genes are to each other and the likelihood of them being separated by crossing over. See the sample human gene map. Sex Linkage A sex linked condition on the Y chromosome will not show in females. XY’ X linked recessive traits show up more in males as they only have one X chromosome so if they gain that allele from their mother, they will have that trait. X’Y For a female to show an X linked trait they must have two copies of the allele. X’X’ Examples of sex linked traits: haemophilia, red green colour blindness, muscular dystrophy Example Exam Question Discuss how and why the different processes that can occur during meiosis can lead to genetic variation between individuals. Take into account the following: • independent assortment • segregation • recombination / crossing over.