BIOLOGY2 #2

NON MENDELIAN LAW

- incomplete dominance
- co dominance
- multiple alleles
- sex-linked traits

INCOMPLETE DOMINANCE

- the heterozygote is intermediate in appearance between 2 homozygotes. Neither allele is completely dominant over the other allele

INCOMPLETE DOMINANCE

when 2 contrastin alleles are present

CODOMINANCE

most genes in a population possess several different alleles, and often no single allele is dominant; instead, each allele has its own effect and the heterozygote shows some aspect of the phenotype of both homozygotes.

CODOMINANCE

2 contrasting alleles are present in the same locus, then the phenotype expressed is a ''blend'' of the 2 extreme phenotype

CODOMINANCE

It can be distinguished from incomplete dominance by the appearance of the heterozygote. In heterozygous condition, both alles are expressed equally with NO blending.

MULTIPLE ALLELES

more than 2 types of alleles for a given locus or trait

MULTIPLE ALLELES

in here, a gene may have 3 or more alleles. A character that is determined by three or more alleles will result in the formation of more genotypes and phenotypes than that predicted by mendel

2 SEX LIMITED TRAITS

inclusive only in 1 sex; 1 carrier 1 sufferer
- any trait in a diploid organism whole expression is limited to just one biological sex, a trait that occurs at a higher frequency
- hormonal

SEX DETERMINATION

- esd afterr conception
- depend on ur enviroment
- what u can consume

GENOTYPE SEX

during conception

DROSOPHILIA

- ideal for the study of genetics and development

DROSOPHILIA

- 75% of the genes that cause disease in humans

POLYTENE

- they are oversized and have barcode-like banding patterns of light and dark

BAR BODY

- a small densely staining structive in the cell nuclei of female mammals, consisting of a condensed, inactive x chromosome.
- chromatin

RED QUEEN HYPTOTHESIS

- a species must adapt and evolve not just for reproductive advantage but also for survival because competing organism also are evolving

SEX-LINKED TRAITS AND CHROMSOMES

- autosomes are the "normal" or body chromosomes while sex chromosomes (x or y) contain sex-linked genes.

SEX-LINKED TRAITS AND CHROMSOMES

specific pairs of these sex chromosomes are what determine our sex. The genes on each chromosome code for proteins that help us develop biologically into males or females

SEX-LINKED TRAITS AND CHROMSOMES

males are usually heterogametous since they have a large X chromosome and a much smaller Y chromosome (YX)

SEX-LINKED TRAITS AND CHROMSOMES

females are usually homogametous since they have 2 large X chromosome (XX)

SEX-RELATED TRAITS

- sex-limited traits
- sex-influenced traits
- sex-linked traits

SEX-LIMITED TRAITS

- These are traits that are visible only within 1 sex
- A sex-limited characteristic is encoded by autosomal genes that are expressed in only one sex

SEX-LIMITED TRAITS

These genes are present in both sexes of sexually reproducing species. Although they are present in both the sexes they are expressed in only one sex while in the other they remain "turned off", which means that the trait has 0 penetrance in the other sex

SEX-INFLUENCED TRAITS

- if a male has one recessive allele, he will show that trait, but it will take 2 recessive for the female to show the same trait

SEX-LINKED TRAITS

- a trait in which a gene is located on a sex chromosome
- Y-linked traits are rare because there are fewer genes in the Y chromosome. There are also none currently well understood besides infertility

SEX-LINKED TRAITS

- X-linked traits can be recessive or dominant and are more common. This is because the X chromosome is large and contains many more genes than the smaller Y chromosome.

SEX-LINKED TRAITS

- X-linked disorders are more common in males than in females.