17.2 Genetics and inheritence 2

What is autosomal linkage/linked genes

Genes located on same chromosome/autosome (not sex related), close enough together on the same chromosome that two genes tend to be inherited together.

Do linked genes go through independent linkage?

No, linked genes do not undergo independent assortment.

Do chromosomes of autosomal linkage/linked genes do through independent assortment?

No. Chromosomes still undergo independent assortment during meiosis.

Autosomal linkage vs linked genes, what is the difference between them?

Linked genes refer to two or more genes located on same chromosome that tend to be inherited together while Autosomal linkage is a specific classification of this that occurs on autonomes (non-sex chromosomes).

What is the relationship between gene loci and likelihood of crossing over occurring?

The further the gene loci of the two genes on same chromosome, the greater the likelihood of crossing over occurring, higher chance of alleles of genes being inherited together is lowered, higher chances of forming recombinant gametes.

What are gene loci that are completely linked

Two gene loci very close to one another, no crossing over takes place.

Will completely linked gene loci result in recombinant gametes

No, no crossing over takes place as two genes are very close to each other.

Why is it that phenotypes of parental flies are represented in higher numbers amongst offspring flies? (And not Mendelian offspring phenotypic ratio 1:1:1:1)

This is due to autosomal linkage, where parental genes are located on the same chromosome. Therefore, they do not undergo independent assortment during during meiosis, and tend to be be inherited together as a single unit or linkage group.

Why is it recombinant types are represented in lower numbers amongst among offspring (and to 1:1:1:1 in Mendelian)

Recombinant gametes are formed as a result of crossing over. As such, the number of recombinant PS1 is dependent on the proximity of the linked genes. Therefore further the distance between two linked genes, the greater the chance of crossing over, and thus higher percentage of recombinant offspring.

What is recombination frequency

Total percentage of recombinant offspring

What is epistasis

Two or more genes determine a single phenotype. Gene products of different genes are involved in the same biochemical/metabolic pathway or same development pathway. Phenotypic expression of a gene (epistatic) at one locus masks the phenotypic expression of a gene at a second locus (hypostatic)

Usually precursor molecule most to the right/final is converted into the darkest or lightest pigment/colour

Darkest

If p>0.05 do we reject H0?

No, we do not reject H0. (very high probability that it is due to chance) There is no significant difference between observed and expected results, any difference is due to chance alone.

Can we say that we accept h0?

No. There is no evidence against hypothesis being true.

If p<0.05% do we reject p0?

yes, reject H0. Difference between observed and expected results is significant and ant difference is due to other factors other than chance alone. This indicates that this inheritance do not follow mendel’s law.

What is polygenic inheritance?

The addictive effect of two or more (usually many) genes on a single phenotypic character

What is continuous variation?

Observable phenotypic pattern in a population where traits vary along a smooth continuum in gradations with no distinct groupings.

What is the relationship Between continuous variation and polygenic inheritance

Continuous variation indicates polygenic inheritance. Continuous variation usually caused by polygenic inheritance, with phenotype modified by environmental factors.