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Flashcards in Genes/Inheritance Deck (14)
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1
Q

Whats hemizygous?

A

Only one copy of gene e.g. X linked

2
Q

What is it when two alleles of a gene are both expressed neither being dominant or recessive to other?

A

Codominance

3
Q

If something is rare in exam question can assume it is

A

Recessive

4
Q

Can you be homozygous dominant

A

Can be but unlikely, normally assume in exam that its heterozygous

5
Q

Define genotype, phenotype, inheritance (exam Q)

A

Geno - genetic makeup of an organism, with reference to a gene or the whole genome

Pheno - Observational characteristics of an individual defined by genotype and environment

Inheritance - Genetic characteristics transmitted from parents to offspring via alleles.

6
Q

What is it called if one gene is responsible for a phenotype? 2 genes? Given an example of a polygenic disease

A

Monogenic

Polygenic

Albinism

7
Q

How is albinism inherited? What does this mean for 2 albinos offspring? What is this phenomena called

A

2 genes 2 alleles, recessive manner
Means their offspring less likely to get albinism as two types of gene ‘compliment’ each other so you get normal phenotype

8
Q

If two genes are on the same chromosome they are said to be _______

A

Linked

9
Q

Do linked genes independently sort at meiosis? What if they are really far apart?

A

No. If really far apart then yes almost behave like separate genes (i.e more likely to cross-over to separate chromosomes, genes that are close together are more likely to stay on same chromosome, or both go to other chromosome).

10
Q

Why does polygenic inheritance not lead to 1:1:1:1 offspring if the 2 genes are on the same chromosome?

A

Because it depends how much cross-over occurs at meiosis to how much 2 of the 4 allele combinations occur.

11
Q

Are X-Linked dominant and recessive males both phenotypic?

A

Yes as only one X chromosome so no difference. Difference is when they pass on to daughters as X linked dominant males will give condition to all daughters, X linked recessive won’t necessarily.

12
Q

If you have a pedigree of two genes that are linked, and it shows a low rate of recombination ~10% of genes for example what could you say about the 2 genes?

A

They are closely linked therefore less likely to independently assort, more likely to travel together in meiosis and therefore less recombination.

13
Q

Define progeny?

A

Child of a gamete that has undergone recombination of genes

14
Q

When does crossing over occur in meiosis? When does random assortment occur?

A

Crossing over - prophase I

Random assortment - metaphase I